Search

16-Methylene-17 alpha-hydroxy-19-norpregn-4-ene-3,20-dione 1 and its 17 alpha-acylated derivatives were synthesized. The length of the 17 alpha-side-chain ranges from C2-C6. As anticipated, compound 1 did not show any progestational activity or receptor binding activity; whereas, the acylated compounds, especially the butyrate, showed remarkable ability to bind to progesterone receptors. These compounds also showed progestational activity in an in vitro T47D cell culture assay in which progestins increase alkaline phosphatase activity and in an in vivo ovulation inhibition assay. All of the compounds synthesized were without estrogenic activities. The results showed that acylation of 16-methylene-17 alpha-hydroxy-19-norprogesterone can increase progestational activity. The progestational activities of these compounds varied with the 17 alpha-side chain.

Development of a male hormonal contraceptive has been challenging ascribable to the failure to adequately suppress spermatogenesis in 5-10% of men. Methods to identify incomplete suppressors early in treatment might identify men most responsive to male hormonal contraceptives. We hypothesized that serum hormone and gonadotropin concentrations after 4 weeks of transdermal treatment with testosterone and Nestorone in a contraceptive trial would be associated with suppression of sperm concentrations to

One-pot synthesis of an 18-norsteroid compound, 13(R),14(R)-epoxy-17β-methyl-20(S)-hydroxyl-18-nor-pregna-4-en-3-one has been achieved with peracetic acid/acetic acid under a mild condition, via a proved tandem epoxidation-rearrangement-epoxidation sequence. Its structure was designated on the basis of NMR and X-ray crystallography data.

Progesterone is a steroid hormone that is essential for the regulation of reproductive function. The main physiological roles of this hormone have been widely described. Progesterone and progestins have been approved for a number of indications including the treatment of irregular and anovulatory menstrual cycles and, when combined with estrogen, for contraception, and the prevention of endometrial hyperplasia in postmenopausal hormonal replacement therapy (HRT) regimens. Lack of understanding between the differences in categories of the progestins as well as with the physiological hormone has resulted in considerable controversy surrounding the use of progestins for HRT regimens. Newer evidence suggests that there are distinct differences between the molecules and there is no progestin class effect, with regard to benefits or side-effects. In addition to its role in reproduction, progesterone regulates a number of biologically distinct processes in other tissues, particularly in the nervous system and the vessels. Recently, it has been shown in animal experiments that progesterone and the progestin Nestorone(®) have positive effects on neuroregeneration and repair of brain damage, as well as myelin repair. The potential benefits of natural progesterone and its related derivatives warrant further investigation. It is hoped that a better understanding of the mechanism of action of progesterone and selected progestins will help in defining better therapies for men and women.

For the synthesis of [18F]Fluoro-Org 6141 via a nucleophilic substitution reaction with 18F-, the tosyl group was chosen as the leaving group because of its stability and excellent leaving group ability. The biodistribution of the high affinity and moderate lipophilicity (log P = 2.66, calculated value) ligand [18F]Fluoro-Org 6141 (specific activity 8.2 to 37 TBq/mmol, yield 10% at EOB) was examined in sham adrenalectomized (sADX) and adrenalectomized (ADX) male Wistar rats. Two days after ADX or sADX, the animals were anesthetized and 0.37 to 1.85 MBq of [18F]Fluoro-Org 6141 was administered intravenously. Kinetics of 18F activity uptake were monitored for 3 h using a stationary double-headed positron emission tomography (PET) camera, and the biodistribution was assessed by ex vivo determination of radioactivity in several tissues and different brain areas. One hour after injection of the radioligand, the bladder, kidney, liver, trachea, and bone of sADX animals contained more concentration on a wet weight basis than blood. Three hours post injection, radioactivity was retained in bladder, trachea, and bone. The accumulation of radioactivity in brain corresponded to the concentration of activity in the blood within the first hours after injection. ADX animals showed a higher uptake of 18F activity in spleen, testes, and brain areas (hippocampus and brainstem) but a lower uptake in bone than sADX rats. PET scans suggested that 18F activity uptake in the brain had not yet reached a maximum at this interval. Although [18F]Fluoro-Org 6141 is not useful for PET studies of glucocorticoid receptors (GRs), the results obtained with this compound indicate a synthetic strategy suitable for the synthesis of high-affinity radioligands for GRs.

Estrogen receptors of human endometrial cancer Ishikawa cells were found to be present in moderate amounts (160–200 fmol/mg protein), and to specifically bind moxestrol (R2858) with a very high affinity characterized by a Kd around 60 pM, when measured under equilibrium conditions. The binding specificity respected a decreasing order as follows: estradiol (E2: 100%) > 4-hydroxy-tamoxifen (4OHTAM: 52.7%) > estriol(E3: 5.7%) > estrone(E1: 2.1%) > TAM (0.2%). The induction of alkaline phosphatase activity (APase) used as an estrogen-specific response, confirmed the intrinsic estrogenicity of progestins derived from 19-nor-testosterone (19NT): norethindrone (NOR), norethynodrel and levonorgestrel, at concentrations ranging from 10−8 to 10−6 M. The effect of NOR was partially blocked by the antiestrogen 4OHTAM, which was also partially agonistic in this model, but neither by the antiprogestin mifepristone (RU486) nor by the aromatase inhibitor aminoglutethimide. A simulatory effect was also detected at 10−7 or 10−6 M with ethindrone, the testosterone- (T) derived progestin homologous to NOR, and with both androgenic parent-compounds, i.e. T and 19NT themselves. In contrast, progesterone (P) derivatives like medroxyprogesterone acetate (MPA) and chlormadinone acetate (CMA) remained totally inactive, as well as 19-nor-progesterone (19NP) itself or its progestagenic derivatives: ORG 2058 and nomegestrol acetate (NOM). Structure-activity relationships deduced from these studies suggest that it is not the absence of the 19-methyl group which can account for the estrogenic potential of the so-called “19-norprogestins”, but rather their steroid structure derived from T in a broad sense (including the 19NT derivatives), as opposed to the non-estrogenic therapeutic progestins derived from P like MPA or CMA, or from 19NP like NOM.

The concept of transdermal delivery (TD) for steroid application has nowadays been largely accepted for hormone replacement therapy in the menopause. It is only recently that the same concept has been envisaged for contraception. The skin can be penetrated by both estrogens and progestins, provided they are delivered in an appropriate solvent. About 10% of the total dose applied topically is actually absorbed. The transdermal delivery systems (TDS) presently available are either of the reservoir type (membrane-moderated system) or of the matrix dispersion type where the drug is dispersed into a polymer matrix. Estradiol (E2) is the most appropriate steroid for TD and can be combined with progestins to ensure a contraceptive effect. Only potent progestins should be used to achieve effective plasma levels with low doses in order to maintain an acceptable small surface of TDS. TDS changed weekly and delivering both E2 and levonorgestrel (L-NG) at daily dosages of 38.4 (+/- 7.5) and 28.8 (+/- 7.2) micrograms/10 cm2 per day respectively, showed ovulation suppression. Another progestin derived from norprogesterone (ST 1435) has been shown to penetrate the skin when suspended in acetylated lanolin or dissolved in a hydroalcoholic gel and to ensure ovulation suppression at a dose of 2 mg per day in a small number of cycles. These preliminary data demonstrate the feasibility of suppressing ovulation in women by transdermal absorption of steroids. Using TDS for contraception implies that such systems should be perfectly adhesive, well tolerated locally and achieve nearly 100% efficacy. These targets are very challenging, however, the potential advantages are so high that the concept deserves further development.The transdermal delivery of steroids (TD) is gaining ground in hormone replacement therapy during menopause. This approach to treatment, however, has only recently been envisaged for contraception. Delivered in the appropriate solvent, both estrogens and progestins can penetrate the skin. Approximately 10% of any total dose applied topically is actually absorbed systemically. Currently available TD systems (TDS) are either of the reservoir type or of the matrix dispersion type in which the drug is dispersed into a polymer matrix. Estradiol is the most appropriate steroid for TD and can be combined with progestins to ensure a contraceptive effect. The use of potent progestins allows effective plasma levels to be reached with low doses through application over a small area of skin. TDS changed weekly and delivering both estradiol and levonorgestrel at daily dosages of 38.4 and 28.8 mcg per 10 sq. cm daily, respectively, was found to suppress ovulation. ST 1435, a synthetic progestin derived from 19-norprogesterone, has also been shown to penetrate the skin when suspended in acetylated lanolin or dissolved in a hydroalcoholic gel and to suppress ovulation at a dose of 2 mg per day in a small number of cycles. TD systems should be perfectly adhesive, well-tolerated locally, and nearly 100% effective.

The clinical performance and the in vivo release rate of a single 4-cm Nestorone subdermal implant were investigated. Implants manufactured by two different procedures were compared. Volunteers were 70 healthy women of proven fertility. Forty women provided blood samples twice a week in the pretreatment cycle and for 5-6 weeks at 6-month intervals during treatment. Additional control cycles (n = 31) were studied in 19 Copper T users. No pregnancy occurred in 1570 woman-months. Nestorone plasma levels (x +/- S.E.) declined from 112 +/- 8 to 86 +/- 3 pmol/L (Implant A) and from 145 +/- 8 to 57 +/- 5 pmol/L (Implant B) from the first to the 24th month. Progesterone levels were9.5 nmol/L in 166 (93%) of 178 blood samplings taken during treatment. Progesterone levels16 nmol/L were found in only 7 sampling periods (3.9%) in treated women and in 70 (98.6%) out of 71 control cycles. No ovulation occurred with Nestorone plasma levels above 105 pmol/L. No abnormal changes were observed in plasma lipoproteins or other clinical chemistry parameters during treatment. The implants were well tolerated. The most frequent complaint was the occurrence of irregular bleeding. Enlarged follicles found during pelvic examination in 8 subjects (11.4%) disappeared spontaneously in 10 days to 6 weeks. Implants were removed because of medical (n = 10, 14.3%) or personal reasons (n = 6, 8.6%) or at the 24th month of treatment (n = 54, 77.1%). The estimated average daily in vivo release rate of Nestorone was 45-50 micrograms/day. A single Nestorone subdermal implant affords efficient contraceptive protection during two years.

Combinations of testosterone (T) and nestorone (NES; a nonandrogenic progestin) transdermal gels may suppress spermatogenesis and prove appealing to men for contraception.The objective of the study was to determine the effectiveness of T gel alone or combined with NES gel in suppressing spermatogenesis.This was a randomized, double-blind, comparator clinical trial conducted at two academic medical centers.Ninety-nine healthy male volunteers participated in the study.Volunteers were randomized to one of three treatment groups applying daily transdermal gels (group 1: T gel 10 g+NES 0 mg/placebo gel; group 2: T gel 10 g+NES gel 8 mg; group 3: T gel 10 g+NES gel 12 mg).The main outcome variable of the study was the percentage of men whose sperm concentration was suppressed to 1 million/ml or less by 20-24 wk of treatment.Efficacy data analyses were performed on 56 subjects who adhered to the protocol and completed at least 20 wk of treatment. The percentage of men whose sperm concentration was 1 million/ml or less was significantly higher for T+NES 8 mg (89%, P0.0001) and T+NES 12 mg (88%, P=0.0002) compared with T+NES 0 mg group (23%). The median serum total and free T concentrations in all groups were maintained within the adult male range throughout the treatment period. Adverse effects were minimal in all groups.A combination of daily NES+T gels suppressed sperm concentration to 1 million/ml or less in 88.5% of men, with minimal adverse effects, and may be further studied as a male transdermal hormonal contraceptive.

Assessment of estrogen receptors and progesterone receptors (PR) with PET may allow the determination of the hormone responsiveness of tumors without the need for multiple biopsies, and the monitoring of the effect of hormonal therapy. In spite of the favourable characteristics of 21-[ 18 F]fluoro-16α-ethyl-19-norprogesterone ([ 18 F]FENP) found in preclinical studies, the compound failed to reveal the presence of PR in breast carcinomas and meningiomas. In view of the clinical significance of the PR assay in human breast cancer, it is worthwhile to explore mechanisms that are potentially involved in the inadequacy of [ 18 F]FENP to image PR with PET. Our present study on the in vivo metabolism of [ 18 F]FENP in humans demonstrates a rapid clearance and biotransformation of the compound. Results of incubation experiments suggest that the metabolic conversion of [ 18 F]FENP is not restricted to the liver, but also occurs in blood cells (presumably the erythrocytes) and tumors (breast carcinomas and meningiomas). The predominant metabolite of [ 18 F]FENP in plasma during the rapid distribution phase and in tumors is identified as 20-dihydro-[ 18 F]FENP. The conversion of [ 18 F]FENP to its 20α- or 20β-hydroxy metabolite has a deleterious effect on the binding affinity for PR. Our findings do not justify a conclusion as to the extent of in vivo extrahepatic biotransformation of [ 18 F]FENP, or its significance in the ineffectiveness of [ 18 F]FENP as an imaging agent for PR. On the other hand, the ability of breast carcinomas and meningiomas to metabolize [ 18 F]FENP avidly appears to preclude selective imaging of PR in these tumors during the time of a PET examination. It is imperative to evaluate the metabolic stability of a [ 18 F]fluorine labeled progestin in an early stage of future screening procedures.

Parenterally administered ST 1435 (Nestorone) is highly potent for contraception, and ovulation can be inhibited with very low serum levels of ST 1435. Orally administered ST 1435 is ineffective in various laboratory animals, presumably due to extensive first-pass metabolism. Thus, ST 1435 has been proposed for lactational contraception, to be metabolized by the suckling infant. We have studied the metabolism of ST 1435 in female volunteers following oral (10 mg), intravenous (iv) (0.1 mg) and transdermal (4.5-9.0 mg) routes of ST 1435 administration. Preliminary studies using rats were performed to develop the methodology of high performance-liquid chromatography (HPLC) fractionation and ST 1435-RIA detection. Rat portal serum revealed 4 distinct peaks of immunoreactive material with the retention times (Rt's) of 7.5, 10, 14.5 and 17.5 min (ST 1435 = 10 min). In systemic serum, only the peak with the Rt of 7.5 min could be detected. Therefore, orally administered ST 1435 is very effectively metabolized by the rat liver; this also explains the previously observed lack of biological effects of oral ST 1435. Following oral administration of ST 1435 to two women, the Rt of the major peak was 10 min. The magnitude of the ST 1435 peak decreased rapidly, and at 24h following ingestion, no ST 1435 could be detected by this method. The t1/2 of ST 1435 was approximately 1-2h. In addition, two minor peaks with Rt's of 4.5 and 16 min could be detected with the ST 1435 RIA at 1-4h following oral ingestion. Competitive receptor binding assays using the human uterine progesterone receptors (hPR) revealed that the ST 1435 fraction exhibits strong binding affinity towards the hPR; thus, in the human, a small fraction of biologically active ST 1435 seems to escape from the first-pass metabolism following oral intake. Following iv and transdermal administration of ST 1435, the only detectable peak with ST 1435-RIA was that of ST 1435. Similar magnitude of the ST 1435 peaks following oral administration of 10 mg and iv administration of 0.1 mg indicated that the bioavailability of ST 1435 is low. These data seem to confirm the suspicion that orally administered ST 1435 is also rapidly metabolized in the human, therefore encouraging further evaluation of ST 1435 during lactation. However, the rapid metabolism seen after oral intake can be successfully circumvented by sustained parenteral administration of ST 1435.

We have prepared and evaluated three metal conjugates of a progestin-monoamine-monoamide (MAMA') bisthiol chelate system. These conjugates of rhenium and technetium-99 and -99m, are structural analogs of the bisamino-bisthiol (BAT) conjugates we have described recently, but the MAMA' chelate, being more polar than the BAT system, gives a conjugate that is much less lipophilic, having an octanol-water partition coefficient that is nearly 80-fold lower. In competitive binding assays, the Re- and 99Tc-MAMA'-progestin conjugates bind to the progesterone receptor with affinities greater than that of progesterone itself, and in a direct binding assay, the equilibrium dissociation constant (Kd) of the 99mTc-MAMA' conjugate was 0.97 nM. As is typical for 11 beta-substituted progestins, these conjugates also have substantial binding affinity for glucocorticoid receptors. In tissue distribution studies in immature female rats, the progestin-99mTc-MAMA' conjugates show selective uptake for principal target tissue (such as uterus) over that of blood and nontarget tissue (such as muscle); these uptake ratios reach maximum levels of 5 and 4, respectively. Uptake by fat, liver, and kidney is quite high; however, only the uptake in uterus is displaceable upon coinjection of the selective progestin ORG2058. Metabolism studies show that the radioactivity in the uterus is essentially unmetabolized out to 4 h, while liver activity is completely due to metabolites. Other tissues show an intermediate fraction of unmetabolized conjugates that decreases with time. The in vivo behavior of the progestin-99mTc-MAMA' conjugate is similar to that of the labeled BAT conjugate: its uptake selectivity is somewhat greater than that of the BAT conjugate, but its target tissue uptake is lower. Factors that may be responsible for limiting the target tissue uptake properties of these conjugates are their moderate affinity for progesterone receptor, their substantial binding to glucorticoid receptors, and their large overall molecular size.

Enhancing the endogenous capacity of myelin repair is a major therapeutic challenge in demyelinating diseases such as multiple sclerosis. We found that progesterone and the synthetic 19-norprogesterone derivative 16-methylene-17α-acetoxy-19-norpregn-4-ene-3,20-dione (Nestorone) promote the remyelination of axons by oligodendrocytes after lysolecithin-induced demyelination in organotypic cultures of cerebellar slices taken from postnatal rats or mice. The intracellular progesterone receptors (PR) mediate the proremyelinating actions of Nestorone, because they are not observed in slices from PR knockout mice. Notably, Nestorone was less efficient in heterozygous mice, expressing reduced levels of PR, suggesting PR haploinsufficiency in myelin repair. Using mice expressing the enhanced green fluorescent protein (EGFP) under the control of the proteolipid gene promoter, we showed that both progesterone and Nestorone strongly increased the reappearance of cells of the oligodendroglial lineage in the demyelinated slices. In contrast to Nestorone, the pregnane derivative medroxyprogesterone acetate had no effect. The increase in oligodendroglial cells by Nestorone resulted from enhanced NG2(+) and Olig2(+) oligodendrocyte progenitor cell (OPC) recruitment. In cocultures of lysolecithin-demyelinated cerebellar slices from wild-type mice apposed to brain stem slices of proteolipid gene promoter-EGFP mice, Nestorone stimulated the migration of OPC towards demyelinated axons. In this coculture paradigm, Nestorone indeed markedly increased the number of EGFP(+) cells migrating into the demyelinated cerebellar slices. Our results show that Nestorone stimulates the recruitment and maturation of OPC, two steps which are limiting for efficient myelin repair. They may thus open new perspectives for the use of progestins, which selectively target PR, to promote the endogenous regeneration of myelin.

Background Discriminant analysis (DA) was performed on data of two combined hormonal contraceptives (CHC) differing in estrogen ratio to explore whether a combination of variables rather than a single variable distinguishes CHCs better. Study Design Data were used of a parallel study in premenopausal women treated for three cycles (21 days on, 7 days off) with a contraceptive vaginal ring delivering Nestorone and ethinyl estradiol (EE) or an oral contraceptive containing levonorgestrel and EE. DA was performed on the change from baseline (CFB) and the end-of-treatment values at 3 months for lipids, sex-hormone binding globulin (SHBG), C-reactive protein, angiotensinogen, blood pressure and hemostasis variables, and on the hemostasis variables only. Results For the complete set, the CFB for factor VII (FVII), SHBG and plasminogen (PLG), or end-of-treatment SHBG- and FVII level discriminated the treatments best. Maximal discrimination for the hemostasis data was by CFB for FVII and PLG or end-of-treatment FVII level. Conclusions DA identifies differences between CHCs and may provide information on the factors associated with thrombotic risk.

The ovulation inhibiting potency of the synthetic progestin ST 1435 (Nestorone) is high after parenteral administration and practically nil after oral administration. The purpose of this study was to determine the pharmacokinetic parameters of ST 1435 after single oral or intravenous administration or after long-term treatment with subdermal implants in women. After administration, as a single i.v. bolus, the plasma disappearance rate of immunoreactive ST 1435 had two components with half-lives (mean +/- SE) of 3.5 +/- 0.5 and 83 +/- 14 min, respectively. The volume of distribution was 4.7 +/- 1.3 L/Kg and the metabolic clearance rate was 55 +/- 6 L/Kg/d. After oral administration, the bioavailability was about 10% of the dose. After chronic subdermal administration, the plasmatic clearance was slower than following the acute doses. These results show that ST 1435 has shorter half-lives and a faster clearance rate than progestins which bind SHBG. The large volume of distribution indicates accumulation in the extravascular space and was expected in view of the high affinity of ST 1435 for progesterone receptors. The slower plasma elimination rate after chronic administration was attributed to the re-entry of a larger mass of drug from the extravascular space, and/or accumulation of immunoreactive metabolites with slower clearance than the parent steroid.

Previous studies have shown that administration of testosterone (T) alone or combined with a progestin has considerable contraceptive efficacy in men. Retrospective data from most hormonal male contraceptive studies have shown that addition of a progestin to testosterone (T) increased the rate and extent of the suppression of spermatogenesis. Nestorone (NES), a progesterone derivative without androgenic or estrogenic activity, has been investigated in women as a potential contraceptive but has not been studied in men. This prospective, randomized, open-label, 2-center trial investigated the effectiveness of transdermal NES gel alone, or in combination with T in suppressing gonadotropin, a surrogate marker for suppression of spermatogenesis. The study subjects were 100 healthy male volunteers who were randomized to 20 days of daily application with 1 of 5 groups (20 per group): either 2 or 4 mg NES (groups 1 and 2); 10 gm of T gel (group 3); or 10 gm of T gel plus either 2 or 4 mg NES (groups 4 and 5). Because there was suboptimal suppression of serum gonadotropins (0.5 IU/L or less) in about half of the study subjects in group 5 (daily 10 gm of T gel plus 4 mg NES), 2 additional groups were randomized to apply a higher dose of NES: daily 10 gm T gel plus either 6 or 8 mg NES gel (groups 6 and 7). The primary study outcome was the percentage of study subjects who had serum luteinizing hormone and follicle-stimulating hormone suppressed to 0.5 IU/L or less after 20 days of treatment. Of the original 140 volunteers, 16 were not efficacy evaluable because of noncompliance with the gel application and 5 withdrew primarily due to adverse reactions. The remaining 119 study subjects were compliant and had few serious adverse events. Both the NES alone and the T gel alone suppressed gonadotropins significantly but the reduction was greater with the T gel alone. The use of the higher doses of the NES gel (6 or 8 mg/d) in combination with the 10 gm T gel suppressed serum gonadotropin levels to less than 0.5 or 1 IU/L in significantly more men than either gel alone (P < 0.05). These findings demonstrate that the use of higher doses of NES (6 mg/d or higher) in combination with T gel has a substantial additive effect on the suppression of gonadotropins and is well tolerated.

The existence of biosynthetic pathways leading to the formation of 19-nor-androgens and corticoids have been established in animals and humans. The exact biologic function of the products of these pathways in vivo has yet to be established; however, it has been shown that they possess pronounced biologic activity when administered exogenously. This report describes the identification of 19-nor-progesterone isolated from the urine of pregnant rats. The procedures used included isolation as the underivatized material and methoxime derivative by thin-layer and high-performance chromatography. The identity was further confirmed by gas chromatography/mass spectral analysis of the isolated product as the 3,20-bis-methoxime derivative. The spectra obtained from the urinary product and the authentic 19-norprogesterone-3,20-bis-methoxime were identical. A possible biologic role for 19-norprogesterone or its precursors is discussed.

Three 21-fluoro-progestins were investigated as potential imaging agents for the in vivo assessment of human progesterone receptor positive neoplasms with positron emission tomography. In competitive binding assays these compounds demonstrated high specificity, competing only for progesterone receptors. Binding to other steroid receptor types was negligible. Based on its high affinity binding, 21-fluoro-16α-methyl-19-norprogesterone was selected for further evaluation in vivo. Tissue distribution studies in immature estrogen primed female rats revealed high uterine uptake of 21-[18F]fluoro-16α-methyl-19-norprogesterone ([18F]FMNP). At 60 min after injection the ratio of uptake of radioactivity by uterine tissue to that of blood was 7. This ratio increased to 24 at 180 min. A selective decrease in uterine uptake was observed after administration of [18F]FMNP with excess unlabelled progestin. Rats bearing hormone responsive MT-W9A mammary adenocarcinomas were used to examine [18F]FMNP for tumour uptake. Animals were used irrespective of the phase of the estrous cycle. At 180 min the uterus to blood ratio and the tumour to blood ratio ranged from 3 to 20 and 3 to 17, respectively. Uterine and tumour tissue was assayed for cytosolic estrogen and progesterone receptors using a dextran-coated charcoal method and Scatchard plot analysis. The results indicate that the in vivo uptake of [18F]FMNP by uterine and mammary tumour tissue correlated well with the progesterone receptor concentration (rs = 0.98 and rs = 0.88, respectively). It is concluded that the uptake of [18F]FMNP by progesterone receptor positive tissue in vivo is primarily receptor related and that this uptake is attributable to the progesterone receptor. The study demonstrates the potential applicability of [18F]FMNP and positron emission tomography for imaging progesterone receptor positive neoplasms.

Five synthetic progestins of the 19-nortestosterone type (norethisterone, NET; levonorgestrel, LN; gestodene, GEST; NET-3-oxime, NETO; norgestimate, NGM) were investigated in the in vitro hepatocyte model. Radiolabelled progestins were added to hepatocyte suspensions (3 x 10(6) cells/ml) freshly prepared from female rat, guinea pig, rabbit, dog (beagle) and cynomolgus monkey. Drug level decreases (NET, LN, GEST) and prodrug conversions (NETO, NGM) were followed by radiochromatography (HPLC) for 60 min. In the case of NET and NETO the conversion into ethinyl estradiol (EE2) was quantified by RIA after HPLC separation. Half-lives of drug level decreases (t1/2), areas under the curves (AUC) and metabolic clearance rates (MCR) were estimated for all progestins. For NETO and NGM the percentages of conversion into NET and LN were calculated, respectively, and levels of EE2 determined in the case of NET and NETO. Rat hepatocytes showed an extremely high metabolic activity towards NET, LN and GEST resulting in t1/2 values of below 2 min. Respective values for rabbit hepatocytes ranged from 5-8 min, whereas half-lives calculated for liver cells from guinea pig, dog and monkey were generally above 30 min. A drastic increase in t1/2 was found for NETO (as compared to NET) in hepatocytes from rat, rabbit and monkey but not from guinea pig. Dog hepatocytes degraded NETO about 3 times more rapidly than NET. NGM was degraded much faster than LN in hepatocytes from all species except the rat. Liver cells from guinea pig and dog seem to be able to metabolize the 3-oxime group much more rapidly than hepatocytes from the other animal species. The lowest degree of prodrug conversion of 4% was observed for NGM and dog hepatocytes. Elevated EE2 levels were found in all experiments with NET and NETO. Results of NET, LN and GEST were compared with published in vivo experiments. No correlations were found for t1/2, MCR, and AUC.

The aim of the present study was to evaluate the potential action of Nestorone (alone or in combination with estradiol valerate) on the level of allopregnanolone and of the opioid beta-endorphin in selected brain areas. Wistar ovariectomized rats were given 0.05 mg/(kg day) of estradiol valerate (E2V) or subcutaneous Nestorone at three dose levels: low dose (10 microg/(kg day)), antiovulatory dose (50 micro/(kg day)) and high dose (250 microg/(kg day)) with and without E2V. E2V therapy reversed the reduction of allopregnanolone and beta-endorphin induced by ovariectomy anywhere was analyzed except for the adrenal gland. Nestorone showed no effect on allopregnanolone concentration in serum or any part of the brain tissue when given alone while it had a synergistic increasing effect in allopregnanolone concentration in some parts of the brain (hippocampus, hypothalamus, anterior pituitary and serum) when given at high dose of 250 microg/(kg day) in combination with E2V. At lower doses it possesses a synergistic effect with E2V only in the hippocampus (at 50 microg/(kg day)) and in the anterior pituitary (at 10 and 50 microg/(kg day)). Nestorone administered alone at any dose led to significant increase in beta-endorphin levels in the hippocampus only while, in the high dose group, there was a significant increase in endorphin levels in anterior pituitary and hypothalamus in addition to hippocampus as compared to ovariectomized control rats. In addition, only the highest dose of Nestorone added to estrogen increased beta-endorphin levels of hippocampus and plasma. Thus the lower doses of Nestorone alone or in combination with estrogen do not seem to exert any great effect on both allopregnanolone and beta-endorphin. It is only the highest dose of Nestorone that increases allopregnanolone and beta-endorphin levels in selected brain areas, which are the hippocampus, the hypothalamus, the anterior pituitary and serum/plasma. This suggests that Nestorone at the antiovulatory dose levels may not alter the positive effects of estrogen treatment on mood and behaviour.

Background Limited information is available on the effects of progestins on breast cancer progression and metastasis. Cell migration and invasion are central for these processes, and require dynamic cytoskeletal and cell membrane rearrangements for cell motility to be enacted. Methods We investigated the effects of progesterone (P), medroxyprogesterone acetate (MPA), drospirenone (DRSP) and nestorone (NES) alone or with 17β-estradiol (E2) on T47-D breast cancer cell migration and invasion and we linked some of these actions to the regulation of the actin-regulatory protein, moesin and to cytoskeletal remodeling. Results Breast cancer cell horizontal migration and invasion of three-dimensional matrices are enhanced by all the progestins, but differences are found in terms of potency, with MPA being the most effective and DRSP being the least. This is related to the differential ability of the progestins to activate the actin-binding protein moesin, leading to distinct effects on actin cytoskeleton remodeling and on the formation of cell membrane structures that mediate cell movement. E2 also induces actin remodeling through moesin activation. However, the addition of some progestins partially offsets the action of estradiol on cell migration and invasion of breast cancer cells. Conclusion These results imply that P, MPA, DRSP and NES alone or in combination with E2 enhance the ability of breast cancer cells to move in the surrounding environment. However, these progestins show different potencies and to some extent use distinct intracellular intermediates to drive moesin activation and actin remodeling. These findings support the concept that each progestin acts differently on breast cancer cells, which may have relevant clinical implications.

The recent identification of tetrahydrogestrinone (THG), a non-marketed designer androgen used for sports doping but previously undetectable by established mass spectrometry-based urine drug screens, and its production by a facile chemical modification of gestrinone has raised concerns about the risks of developing designer androgens from numerous marketed progestins. We therefore have used yeast-based in vitro androgen and progesterone bioassays to conduct a structure-activity study assessing the intrinsic androgenic potential of commercially available progestins and their derivatives, to identify those compounds or structures with the highest risk of forming a basis for such misapplication. Progestins had a wide range of androgenic bioactivity that was not reliably predicted for individual steroids by their progestin bioactivity. 17alpha-Hydroxyprogesterone and 19-norprogesterone derivatives with their bulky 17beta-substituents were strong progestins but generally weak androgens. 17alpha-Ethynylated derivatives of testosterone, 19-nortestosterone and 18-methyl-19-nortestosterone such as gestrinone, ethisterone, norethisterone and norgestrel had the most significant intrinsic androgenicity of all the commercially marketed progestins. Facile chemical modification of the 17alpha-ethynyl group of each of these progestins produces 17alpha-methyl, ethyl and allyl derivatives, including THG and norbolethone, which further enhanced androgenic bioactivity. Thus by using the rapid and sensitive yeast bioassay we have screened a comprehensive set of progestins and associated structures and identified the ethynylated testosterone, 19-nortestosterone and 18-methyl-19-nortestosterone derivatives as possessing the highest risk for abuse and potential for conversion to still more potent androgens. By contrast, modern progestins such as progesterone, 17alpha-hydroxyprogesterone and 19-norprogesterone derivatives had minimal androgenic bioactivity and pose low risk.

Objective: We evaluated the effects of a new combined hormonal contraceptive vaginal ring (CVR) delivering the nonandrogenic progestin Nestorone® (NES) and ethinyl estradiol (EE) on several key estrogen-sensitive hepatic proteins that may be markers for the risk of arterial or venous disease events and on blood pressure (BP). Because the pharmacologic androgenicity of the progestin in these formulations influences the hepatic impact of EE, we selected an oral contraceptive (OC) delivering the androgenic progestin levonorgestrel (LNG) and EE as the comparator. We also investigated the effect of delivery route, which is known to modify the hepatic effects of estradiol, but has not been widely studied with EE. Study Methods: Women, aged 18-34 years, with no contraindications to the use of combined OCs, were randomized to three cycles of treatment with a CVR delivering NES/EE (150/15 μg/day) or a combined OC providing LNG and EE (150/30 μg per tablet). Each cycle consisted of 21 days of active treatment, followed by 7 days without treatment. During the last weeks of the pretreatment and third treatment cycles, blood samples were obtained for determinations of plasma concentrations of angiotensinogen, an estrogen-sensitive hepatic protein, and serum concentrations of sex hormone-binding globulin (SHBG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG) and estrogen- and androgen-sensitive proteins. BP was also measured. Results: Of 47 women randomized, 45 completed the study (CVR: 23; OC: 22). Within-group comparisons over time by repeated-measure analysis of variance demonstrated statistically significant changes over time with both treatments for all hepatic proteins (p

Background Transdermal delivery of steroids is gaining popularity for contraception and hormone replacement therapy. This study aimed to test metered spray delivery of a precise dosage of Nestorone® (NES) progestogen as a possible transdermal progestogen-only contraceptive. Study Design Six healthy postmenopausal volunteers, not recently using any hormonal therapies, comprise the sample for this study. Each subject was studied on two occasions with multiple blood sampling for assay of NES over a 24-h period: on the first occasion, after a single dosage of 3×90 μL NES sprays using a specially devised, precisely metered delivery device; on the second occasion, following the fifth in a series of five daily transdermal dosages of 3×90 μL of NES spray. Conventional pharmacokinetic parameters were calculated. NES was assayed in serum using a specific radioimmunoassay. Results Mean serum levels of NES peaked at around 20 h following dosing, and levels plateaued at 285–290 pmol/L after 4–5 days of daily spray application. All subjects achieved satisfactory serum levels, although substantial intersubject variation was noted. The apparent elimination half-life of NES after the last dose on Day 5 was 26.8 h. No unexpected adverse events were encountered. Conclusion This early pharmacokinetic trial of a new transdermal steroid delivery system has demonstrated the feasibility of achieving serum levels of NES sufficient to block ovulation and potentially provide effective contraception.

Objective: This study aimed to compare the effects on hemostasis variables of a contraceptive vaginal ring with those of an oral contraceptive. Study design: Twenty-three and 22 healthy premenopausal women were randomized to the contraceptive vaginal ring (150 μg Nestorone and 15 μg ethinyl estradiol) or Stediril 30 during 3 cycles. Analysis of covariance was performed with baseline values as covariate. Results: The contraceptive vaginal ring changed most hemostasis variables similarly but raised (95% confidence intervals of percent treatment differences) Factor VIIt (28% to 49%), extrinsic activated protein C resistance (14% to 65%), and sex hormone-binding globulin (117% to 210%) and lowered Protein S (-32% to -16%) and the global activated partial thromboplastin time-based activated protein C resistance (-12% to -2%) more than the oral contraceptive. Conclusion: The contraceptive vaginal ring affected some measured hemostasis variables and sex hormone-binding globulin differently from the oral contraceptive, most likely because of difference in androgenicity of the progestins. The results suggest that the contraindications for oral contraceptive use would also apply to the tested contraceptive vaginal ring. © 2006 Mosby, Inc. All rights reserved. Chemicals / CAS: blood clotting factor 7, 9001-25-6; elcometrine, 7759-35-5; ethinylestradiol plus norgestrel, 8056-51-7; ethinylestradiol, 57-63-6; levonorgestrel, 797-63-7; Blood Coagulation Factors; Contraceptive Agents, Female; Contraceptives, Oral, Combined; Estrogens; Ethinyl Estradiol, 57-63-6; Ethinyl Estradiol-Norgestrel Combination, 8056-51-7; Norprogesterones; Plasminogen, 9001-91-6; Protein C; Sex Hormone-Binding Globulin; ST 1435, 7759-35-5

Objective: This study aimed to compare the effects on hemostasis variables of a contraceptive vaginal ring with those of an oral contraceptive. Study design: Twenty-three and 22 healthy premenopausal women were randomized to the contraceptive vaginal ring (150 μg Nestorone and 15 μg ethinyl estradiol) or Stediril 30 during 3 cycles. Analysis of covariance was performed with baseline values as covariate. Results: The contraceptive vaginal ring changed most hemostasis variables similarly but raised (95% confidence intervals of percent treatment differences) Factor VIIt (28% to 49%), extrinsic activated protein C resistance (14% to 65%), and sex hormone-binding globulin (117% to 210%) and lowered Protein S (-32% to -16%) and the global activated partial thromboplastin time-based activated protein C resistance (-12% to -2%) more than the oral contraceptive. Conclusion: The contraceptive vaginal ring affected some measured hemostasis variables and sex hormone-binding globulin differently from the oral contraceptive, most likely because of difference in androgenicity of the progestins. The results suggest that the contraindications for oral contraceptive use would also apply to the tested contraceptive vaginal ring. © 2006 Mosby, Inc. All rights reserved. Chemicals / CAS: blood clotting factor 7, 9001-25-6; elcometrine, 7759-35-5; ethinylestradiol plus norgestrel, 8056-51-7; ethinylestradiol, 57-63-6; levonorgestrel, 797-63-7; Blood Coagulation Factors; Contraceptive Agents, Female; Contraceptives, Oral, Combined; Estrogens; Ethinyl Estradiol, 57-63-6; Ethinyl Estradiol-Norgestrel Combination, 8056-51-7; Norprogesterones; Plasminogen, 9001-91-6; Protein C; Sex Hormone-Binding Globulin; ST 1435, 7759-35-5

The progestins have different pharmacologic properties depending upon the parent molecule, usually testosterone or progesterone (P), from which they are derived. Very small structural changes in the parent molecule may induce considerable differences in the activity of the derivative. In hormonal contraceptives, progestins represent the major agent designed for suppressing ovulation and are used in combination with estrogen (E) usually ethinyl-estradiol (EE). The development of new generations of progestins with improved selectivity profiles has been a great challenge. Steroidal and nonsteroidal progesterone receptor (PR) agonists have been synthesized as well, although the latter are still in a very early stage of development. Several new progestins, have been synthesized in the last two decades. These include dienogest (DNG), drospirenone (DRSP), Nestorone (NES), nomegestrol acetate (NOMAc) and trimegestone (TMG). These new progestins have been designed to have no androgenic or estrogenic actions and to be closer in activity to the physiological hormone P. DRSP differs from the classic progestins as it is derived from spirolactone. It is essentially an antimineralocorticoid steroid with no androgenic effect but a partial antiandrogenic effect. The antiovulatory potency of the different progestins varies. TMG and NES are the most potent progestins synthesized to date, followed by two of the older progestins, keto-desogestrel (keto-DSG) and levonorgestrel (LNG). The new molecules TMG, DRSP and DNG also have antiandrogenic activity. Striking differences exist regarding the side effects among the progestins and the combination with EE leads to other reactions related to the E itself and whether the associated progestin counterbalances, more or less, the estrogenic action. The 19-norprogesterone molecules and the new molecules DRSP and DNG are not androgenic and, therefore, have no negative effect on the lipid profile. Given their pharmacological properties, it is likely that the new progestins may have neutral effects on metabolic or vascular risks. However, this hypothesis must be confirmed in large clinical trials.

The Nestorone/ethinylestradiol (NES/EE) vaginal ring is being developed as a regular contraceptive method by the Population Council. This ring is designed to release NES 150 microg/day and EE 15 microg/day during 1 year. Here, we report a Phase I clinical trial to determine the usefulness of this ring for emergency contraception. To that end, we tested the ability of this ring to interfere with ovulation when it is inserted during the follicular phase.Forty-eight women protected from the risk of pregnancy by nonhormonal methods were divided into three groups, which differed by the size of the dominant follicle at the time of ring insertion: 12-14 mm (n = 16), 15-17 mm (n = 18) andor=18 mm (n = 14) diameter. The NES/EE ring was left in the vagina for 7 consecutive days, after which it was removed. The growth of the leading follicle and plasma levels of estradiol, progesterone (P), luteinizing hormone (LH) and follicle stimulating hormone (FSH) in the ensuing 5 days after ring insertion were determined. Afterwards, steroid hormones were measured twice a week, until menses took place. All women had a control cycle before the ring cycle, and the range of maximum follicular diameter assigned to each volunteer was the same for the control and the ring cycle at the time when placebo was ingested or the ring inserted.During the 5-day period after ring insertion with follicles 12-17 mm, ovulation was absent in 25 of 34 cycles (p.01 vs. control), and ovulatory dysfunction (absent, blunted or mistimed LH peak) occurred in 8 of the 9 remaining cycles (33/34 ovulatory processes altered; p.005 vs. control). After ring insertion with folliclesor=18 mm in diameter, ovulation did not occur in 2 of 14 cycles or was dysfunctional in 7 of the 12 remaining cycles (9/14 ovulatory processes altered; p.025 vs. control). Altogether, 87.5% of ring cycles (42/48) had either no ovulation or ovulatory dysfunction in the 5-day study period, in contrast to 39.6% (19/48 cycles) in control cycles (p.001). Among follicles that failed to rupture within the 5-day study period, none ruptured later on in the ring-treated cycles, while 9 of 16 did so in control cycles. Sixty-two percent of ring-treated cycles were shorter than 24 days. Nausea, vaginal discharge and abdominal pain were the most frequently reported adverse events during ring use.Interference with 87.5% of ovulatory processes, without ovulation occurring later in the cycle and shortening of cycle length, suggests the NES/EE ring may be used as an emergency contraceptive method, with the potential advantage of providing continuing contraception after it has performed its emergency function.

In a multicenter 1-year trial of contraceptive vaginal rings (rings) involving 150 women, three dose combinations of the progestin Nestorone (NES) and ethinylestradiol (EE) were compared with respect to effectiveness, safety and acceptability. Mean in vitro drug release rates for the three doses were 150 and 15, 150 and 20 and 200 and 15 microg/day of NES and EE, respectively. Each ring remained in situ for 21 days, removed for 7 days and then reinserted for a total of 13 cycles of use. We studied ring performance with respect to pregnancy and other termination events, adverse events, the extent of ovulation inhibition, serum drug levels and bleeding control. We also assessed the rings' effects on the vagina using a standardized colposcopy procedure. Seventy-two percent of the women completed the 1-year (> or = 350 days) study. In studied cycles, luteal activity (progesterone > or = 10 nmol/L) was noted in 17%, 7% and 12% of subjects with monitored cycles at the 150/15, 150/20 and 200/15 doses, respectively (p = .34). Two pregnancies occurred, both in subjects using the 200/15 microg/day ring. Breakthrough bleeding during ring use averaged about 2 days/year and breakthrough bleeding and spotting averaged about 7 days/year. In the entire trial, only two women discontinued because of bleeding problems. Medical conditions, chiefly vaginal problems, personal reasons and device loss or repeated expulsion were the principal reasons given for study discontinuation. Vaginal and cervical colposcopy, conducted with standardized techniques and standardized interpretations, revealed no elevated event incidence attributable to ring use. Clinical performance and adverse event profiles indicate that each of these 1-year NES/EE rings, used on a 21-day-in and 7-day-out regimen, provided women effective, acceptable and safe long-acting contraception under their own control.

To evaluate the prevalence of enlarged ovarian follicles among users of a 20 micrograms/d levonorgestrel-releasing intrauterine system (Mirena, Leiras Oy, Turku, Finland), of subdermal contraceptive implants releasing Nestorone (Population Council, New York, New York) and of the TCu 380A intrauterine device.A cohort study was conducted at the Universidade Estadual de Campinas, Brazil. Three hundred women were enrolled, with 100 participants in each group. Bimanual pelvic examination and vaginal ultrasound were performed during routine gynecologic examinations in women without complaints. In women with enlarged ovarian follicles (or = 25 mm), estradiol and progesterone levels were assessed weekly until disappearance or reduction of the ovarian image.Enlarged ovarian follicles were detected in 19%, 10% and 5% of users of the levonorgestrel system, implants and intrauterine device, respectively. Most of the enlarged ovarian images disappeared after 2 weeks of follow-up. Progesterone levels showed that the intrauterine system and TCu 380A IUD (FEI, North Tonawanda, New York) users had presumably ovulated before the first ultrasound examination in contrast to the implant users.Physicians and users should be aware that findings of enlarged ovarian follicles during the use of progestin-only contraceptives are transient and that no medical interventions are necessary.

The development of steroid-releasing vaginal rings over the past three decades is reviewed to illustrate the role of this device as an effective hormonal contraceptive for women. Vaginal rings are made of polysiloxane rubber or ethylene-vinyl-acetate copolymer with an outer diameter of 54-60 mm and a cross-sectional diameter of 4-9.5 mm and contain progestogen only or a combination of progestogen and oestrogen. The soft flexible combined ring is inserted in the vagina for three weeks and removed for seven days to allow withdrawal bleeding. Progesterone/progestogen-only rings are kept in for varying periods and replaced without a ring-free period. Rings are in various stages of research and development but a few, such as NuvaRing, have reached the market in some countries. Women find this method easy to use, effective, well tolerated and acceptable with no serious side-effects. Though the contraceptive efficacy of these vaginal rings is high, acceptability is yet to be established.

Development of contraceptive implant methods, when based on established or on new synthetic chemical entities, is a decadal or multi-decadal process. The process often requires the cooperation of numerous investigators for laboratory work, for early Phase II trials, for dose-finding trials, and for Phase III clinical trials. The Phase III work also requires cooperation with a commercial manufacturer and potential distributor of the product. The Population Council has recently completed developmental work on two levonorgestrel-releasing implants, with filings to regulatory agencies that support extended use of Jadelle implants for 5 years and Norplant implants for 7 years. When the developmental process includes establishing the clinical properties of a molecule not yet approved by regulatory agencies, the minimum development time appears to be two decades. The status and rationale of studies of a new Nestorone-releasing, single implant developed by the Population Council for a period of use of 2 years are presented.

The objective of this study was to evaluate the contraceptive efficacy and clinical performance of a Nestorone subdermal implant (NES) in the postpartum period. NES (n = 100) and Copper T intrauterine device (T-Cu; n = 100) acceptors initiated contraception at 8 weeks postpartum and were followed at monthly intervals during the first year and at 3-month intervals thereafter. Pregnancy rates, breastfeeding performance, infant growth, bleeding pattern, and side effects were assessed. Blood and milk NES concentration were measured. No pregnancy occurred in 2195 and 2145 woman-months of NES implant and T-Cu use, respectively. No effect of NES on lactation and infant growth and no serious adverse events were observed. Lactational amenorrhea was significantly longer in NES users (353 ± 20 days) than in T-Cu users (201 ± 11 days). More NES users (55.8%) experienced prolonged bleedings than did T-Cu users (36.2%). Concentrations of NES in breast milk ranged between 54–135 pmol/liter. The Nestorone implant is a highly effective contraceptive, safe for breastfed infants because the steroid is inactive by the oral route.

Contraceptive vaginal rings (CVRs) contain sex steroids that diffuse through a plastic polymer ring at a constant rate and are absorbed directly through the vaginal epithelium into the systemic circulation. This delivery system provides many advantages over oral contraceptives (OCs), including avoidance of the first-pass effect through the liver, constant serum steroid levels, longer duration of use, and greater bioavailability of the hormones. CVRs containing progestin only are designed for continuous use for 3 to 6 months. Those containing progesterone alone are indicated for use in women who are breastfeeding. Large clinical trials of progestin-containing CVRs demonstrated good efficacy and safety of the CVR, with continuation rates similar to that of OCs. CVRs containing a combination of estrogen and progestin are designed to be used for 1 to 12 months in a cyclic manner similar to OCs, with withdrawal bleeding in the fourth week of each cycle. In clinical trials these CVRs have typical use efficacies similar to OCs, with an acceptable pattern of bleeding.

Contraceptive vaginal rings delivering various progestins alone or in combination with estrogen have been previously studied, showing adequate steroid vaginal absorption and acceptability by the users. Nestorone progestin (NES) is a potent 19-nor-progesterone derivative, inactive by the oral route, but an excellent option for vaginal delivery. The purpose of this study was to evaluate ovarian function during 6 months of continuous use of progestin-only vaginal rings delivering 3 different doses of NES: 50, 75, and 100 microg per day. Blood samples were taken twice a week for 5 consecutive weeks during a control cycle and on months 1, 3 and 6 of use, for the measurement of estradiol (E2), progesterone (P), and NES. A total of 87 volunteers randomly received each of the 3 doses. After an initial peak, NES serum levels remained fairly constant throughout the duration of the study at about 125, 200 and 250 pmol/L, respectively, decreasing slightly with time. Luteal activity occurred very rarely (1.2-2.6% of sampling periods) with no apparent difference between doses. Low E2 levels (or =100 pmol/L) in all samples of a run were rare (5%) and only with the high dose ring (100 microg/day). E2 remained within normal levels (101-1500 pmol/L) in most of the segments studied. We conclude that the 50 and 75 microg/day NES rings provide adequate ovulation inhibition without hypoestrogenism, while the 100 microg/day ring may deliver an unnecessarily high dose.

Genotoxicity evaluations of several different chemicals including L-4-oxalysine, 10-Hydroxycamptothecin (HCT), 19-norprogesteron (ST1435), dimethyl sulfoxide (Me2SO), bleomycin (BLM), and mitomycin C (MMC).Alkaline comet assay in vitro (single cell gel) (SCG).L-4-oxalysine and HCT did not cause directly DNA damage. ST1435, the subdermal implant progestin, had no effect on DNA damage until the dose level up to 4 mmol.L-1. Me2SO did not increase DNA damage at concentration below 2%, but showed a concentration-dependent DNA damage ator = 4%. Bleomycin and mitomycin C demonstrated a strong dose-dependent DNA damage.Comet assay as a tool to test the genotoxicity of suspected chemicals, is rapid, simple, sensitive, good reproducible, and inexpensive.

Nestorone(R) (Nestorone 16-methylene-17alpha-acetoxy-19-norpregn-4-ene-3,20-dione), formerly referred to as ST 1435, is a potent progestin when given parenterally via sustained release formulations. The pharmacological profile of Nestorone was compared with that of levonorgestrel and 3-keto-desogestrel by steroid receptor binding studies and by in vivo bioassays in rats and rabbits. 3-Keto-desogestrel showed the highest binding affinity to progesterone receptors (PR) followed by Nestorone, levonorgestrel, and progesterone. The binding affinity of Nestorone to androgen receptors (AR) was 500- to 600-fold less than that of testosterone. However, both levonorgestrel and 3-keto-desogestrel showed significant binding (40 to 70% of testosterone) to AR. None of the progestins bound to estrogen receptors (ER). The progestational activity of Nestorone, levonorgestrel, and progesterone was compared using McPhail index in immature rabbits and pregnancy maintenance and ovulation inhibition tests in rats after subcutaneous (s.c.) administration. In all three tests, Nestorone was the most potent progestin. The progestational activity of Nestorone was also compared after oral and s.c. administration in rabbits. The potency of Nestorone was over 100-fold higher upon s.c. administration than via the oral route. The androgenic activity of progestins, based on the stimulation of ventral prostate (androgenic target) and levator ani (anabolic target) growth in castrated immature rats, showed good correlation with their binding affinity to AR. Nestorone showed no androgenic or anabolic activity. Nestorone did not bind to sex hormone binding globulin (SHBG), whereas both levonorgestrel and 3-keto-desogestrel showed significant binding to SHBG. The estrogenic/antiestrogenic activity of Nestorone was investigated in immature ovariectomized rats. In contrast to estradiol and levonorgestrel, Nestorone showed no uterotropic activity in ovariectomized rats. Despite significant binding to glucocorticoid receptors (GR), Nestorone showed no glucocorticoid activity in vivo. It is concluded that a strong progestational activity, combined with lack of androgenic, estrogenic, and glucocorticoid-like activities, confer special advantages to Nestorone for use in contraception and hormone replacement therapy.

Nestorone progestin (NES) is a potent 19-nor-progesterone derivative which is biologically inactive when administered orally; however it is an excellent option for implant contraception. The objective of this study was to evaluate ovarian function during use of either one 4-cm or two 3-cm NES implants for 24 months. A total of 60 volunteers were enrolled in each dose group. Vaginal ultrasound (VUS) and blood sampling for determinations of estradiol (E2) progesterone (P) and NES serum levels were carried out twice a week for 6 consecutive weeks beginning in months 1 6 12 18 and 24 of implant use. Serum levels of NES declined with time with a more pronounced decrease during the first 18 months of implant use; thereafter NES levels remained stable until the end of the study at 24 months. Luteal activity was very infrequent during the first year of use (

The relationship between ovarian hormones and bleeding patterns during continuous progestin contraception was studied in 29 women who used Nestorone® (NES) releasing implants. Oestradiol and progesterone were measured in blood samples taken twice a week for 6 consecutive weeks during months 6 12 18 and 24 of implant use. Retrospectively the association between hormonal concentrations and bleeding patterns was evaluated. Twenty-four short (= 24 days) 36 normal (25--35 days) 27 long (36--90 days) and nine episodes of amenorrhoea as well as 28 periods of prolonged bleeding were identified. Short cycles periods of prolonged bleeding and amenorrhoea were characterized by low oestradiol concentrations. Bleeding after a normal or long cycle regularly occurred after a rise and fall of oestradiol or oestradiol and progesterone. The duration of bleeding was directly and significantly associated with the highest concentration of oestradiol in the previous 15 days in anovulatory cycles. Luteal activity was associated with shorter duration of bleeding. Periods of prolonged bleeding were usually initiated with a drop in oestradiol and over half ended with an increase in oestradiol. It was concluded that changes in endogenous hormone have a significant influence over the bleeding pattern during use of NES implants. (authors)

Nestorone (NES) progestin is highly effective for contraception following parenteral administration, but ineffective after oral ingestion due to rapid first-pass metabolism. Thus, NES might be ideal for lactational contraception; possible NES in milk should be metabolized by the nursing infant. We evaluated the distribution of NES, its endocrine effects and infant weight gain in five cynomolgus monkeys and their nursing infants. Nestorone implants, releasing approximately 40 microg NES/day in vitro, were placed s.c. in the mothers 3-4 months following delivery, where they remained in situ for 4 weeks. Sampling (blood daily from the mother; milk and blood from the infant at 3 day intervals) was initiated at 2 weeks prior to insertion, and continued for 2 weeks following removal of the implant. NES, oestradiol, progesterone and prolactin were measured by radioimmunoassays and the infants were weighed weekly. The (mean +/- SD) maternal serum and milk concentrations of NES were 337 +/- 90 and 586 +/- 301 pmol/l during the use of the implants. The ratio of milk/serum NES was 1.68 +/- 0.12 (mean +/- SE), and the serum and milk concentrations were significantly correlated (r = 0. 75, P0.001). NES was not detectable (13 pmol/l) in any infant serum samples. Concentrations of prolactin (mean +/- SD) were 41.1 +/- 32, 26.7 +/- 7.6 and 26.3 +/- 9.5 ng/ml before, during and after the use of the implants respectively. The (mean +/- SE) infant weight increased from 643 +/- 54 g 1 week prior to insertion to 713 +/- 54 g 1 week following removal. These data confirm that NES in milk is rapidly metabolized by the suckling infant. Therefore, NES appears to be an ideal hormonal contraceptive for use during lactation.

Because of its unique features, the contraceptive effectiveness and tolerance during breast-feeding of 16-methylene-17 alpha-acetoxy-19-nor-4-pregnene-3,20-dione (elcometrine), delivered within a single subdermal capsule of medical grade polydimethylsiloxane, was investigated. Unlike other progestational steroids, elcometrine has no affinity for androgen and estrogen receptors and is inactive by the oral route. A total of 66 breast-feeding women receiving elcometrine by the subdermal route were enrolled in the study, and 69 women who elected to use Copper-T380 intrauterine devices (IUD) served as control subjects. The women and their infants were observed until the end of the first postpartum year. There were no significant differences in growth and development measurements among the infants in the elcometrine and control groups. The percentage of infants continuing to breast-feed at 3 and 6 months was significantly higher in the elcometrine group. There were no significant differences between the concentration of elcometrine in the mother's blood and milk. At 75 days, blood levels of elcometrine in the infants were near the undetectable and were significantly lower than the levels in maternal blood or milk (p0.01). In 15 of 25 infants, blood levels of elcometrine were at the limit of assay sensitivity or undetectable. Two pregnancies occurred in women using IUD, whereas none occurred in those using implants. There were menstrual bleeding irregularities in both groups. A single elcometrine capsule placed subcutaneously at 6-monthly intervals appears to be an effective method of contraception for lactating women and results in blood concentrations of nursing infants at or near undetectable levels.Discusses the effects of the use of a single implant of elcometrine (ST-1435), a nonorally active progestin, as a long acting contraceptive for postpartum nursing women in Maternidade Climerio de Oliveira in Salvador, Bahia, Brazil. A total of 135 women aged 18-35 years having a singleton term delivery, fully breast-feeding on demand, planning to breast-feed for 6 months postpartum, and requesting effective contraception were recruited. The method was initiated for 6 weeks postpartum. Results showed that 66 breast-feeding women used elcometrine implants, while 69 women preferred an IUD insertion. The contraceptive efficacy of lactation is high for women breast-feeding on demand, particularly in those who remain in amenorrhea during the 6 months postpartum; in these women, elcometrine implant and IUD prevented pregnancy effectively. Breast-feeding was significantly higher (p 0.05) in the elcometrine group at 3 and 6 months, while at 9 and 12 months there was no statistical difference. The differences in type, frequency of supplementary feeding, and anthropometric measures between the two contraceptive groups were not significant. Menstrual irregularities were present in both groups. Thus, elcometrine could be best alternative and the most effective method of contraception for lactating women.

Through the use of fluorine-18 radiolabeled estrogen receptor ligands and Positron Emission Tomography (PET), imaging of estrogen receptor-positive (ER+) breast lesions has been accomplished. Targeting the estrogen and progesterone receptors found in receptor-positive breast cancer provides a means of diagnosing the disease non-invasively. The structure-activity relationship of evaluated fluorine-18 ligands are summarized and design considerations for construction of novel target ligands discussed. The role of the serum protein sex hormone-binding globulin (SHBG) in transport and metabolism of estrogens is related to target tissue uptake. A historical review of fluorine-18 radiolabeled estrogens includes the clinical study of 16 alpha-[18F]fluoroestradiol-17 beta (18FES) for imaging ER+ breast lesions. The success of 18FES in the clinical setting has shown the significance of PET in imaging primary and metastatic breast cancer by allowing for assessment of tumor response to tamoxifen therapy after as little as 7 days of treatment. Advantages of visualizing the tumor through targeting the progesterone receptor (PR) include PET imaging to follow the progress of tamoxifen therapy while the estrogen receptors are blocked. Clinical studies with the PR ligand 21-[18F]fluoro-16 alpha-ethyl-19-norprogesterone (18FENP) were not successful due to high hepatic uptake and poor correlation of tumor uptake with receptor content. Second generation PR ligands with decreased non-specific binding are predicted to be effective imaging agents for human PR+ breast cancer from studies in the immature rat and are ready for clinical evaluation.

The effects of 6 months of combined hormone therapy with transdermal estradiol (0.05 mg/day x 21 days) and different oral progestogens (10 mg/day medroxyprogesterone acetate [MPA] in the last 12 days, 10 mg/day dihydrogesterone in the last 12 days, and 50 mg/day cyproterone in the first 10 days), on menopausal symptoms and hypothalamo pituitary-ovarian function were studied in normal perimenopausal women. The study included 38 perimenopausal women, aged 43-49 years, with regular cycles of 26-32 days in length and menopausal symptoms. Endocrine status was determined by assay of basal levels of gonadotropins (LH, FSH), E2, and P every week until menstrual bleeding, before and during the first month of therapy. Plasma levels of LH and FSH were suppressed in the first month of therapy while E2 had a mean value of 45 +/- 12 pg/ml. Ultrasound examination and low levels of P indicated a complete block of ovulation and hypothalamo-pituitary-ovarian activity. All women reported the disappearance of vasomotor symptoms and nocturnal sweating. Transdermal estradiol and oral progestogens were well tolerated. This study shows that combined hormone therapy with low doses of transdermal estrogen patches and different oral progestogens reduces menopausal symptoms and also safeguards against unwanted pregnancies in the perimenopausal period.

The stability of the contraceptive steroid, Nestorone (16-methylene-17α-acetoxy-19-nor-pregn-4-ene-3,20-dione) in the solid state and in aqueous solutions, was investigated using reverse-phase high-performance liquid chromatography. In the solid state, whether as a powder or when it is incorporated into Silastic implants, the steroid does not undergo detectable degradation even under severe experimental conditions. In solution, the drug undergoes slow degraduation that is dependent on temperature and pH of the medium. The decomposition is defined by first-order mechanism. As expected, the reaction rate increases with increasing storage temperature. The linearity of the Arrhenius plot indicates that there is no change in the reaction mechanism within the temperature range studied. In alkaline media, the drug degrades at a faster rate through hydrolytic rather than an oxidative mechanism. The major hydrolytic degradation product, 16-methylene-17α-hydroxy-19-nor-pregn-4-ene-3,20-dione, was separated and identified by mass spectrometry.

Subdermal contraceptive implants involve the delivery of a steroid progestin from polymer capsules or rods placed under the skin. The hormone diffuses out slowly at a stable rate, providing contraceptive effectiveness for 1-5 years. The period of protection depends upon the specific progestin and the type of polymer. Advantages of progestin implants include long term contraceptive action without requiring the user's or provider's attention, low dose of highly effective contraception without the use of estrogen, and fertility is readily reversible after the removal of implants. The levonorgestrel implant Norplant R system is the only one that has been approved for distribution. The contraceptive efficacy of Norplant is the highest observed amongst the most effective methods with an annual pregnancy rate of 0.2 during the first and second year and 1.1 on the fifth year. Menstrual problems are the main reason for the discontinuation of Norplant and 9% of women stopped using it during the first year of treatment. Other implants are still under development trying to simplify the method by reducing the number of units and to introduce other progestins that may minimize side effects. Norplant-2 was designed to release the same dose of progestin from only two covered rods. Evaluation of 1400 women enrolled, indicates that over 2 years the cumulative pregnancy rate is below 0.5 per 100 women. There are three single implants under development: Nestorone, 3-Keto-desogestrel and Uniplant that are expected to be effective for 1-2 years. Phase II clinical trials with Nestorone have been completed and no pregnancies have been observed in 1570 woman-months of use. Bleeding irregularities occurred in 20-30% of the women but there were only four terminations because of bleeding problems. A multricentric study is ongoing with a newly designed 3-keto-desogestrel implant named Implanon, which releases approx. 60 micrograms/day of the hormone. The objectives of this study are to assess contraceptive efficacy, safety and acceptability of Implanon. Another multricentric study is ongoing with Uniplant, which releases nomegestrol acetate with a duration of action for only 1 year. The objectives of the trial are to study the endocrine profile of Uniplant users and to evaluate the efficacy and acceptability of the method.Subdermal contraceptive implants deliver progestin from polymer capsules or rods placed under the skin. Diffusing slowly from the polymer containers at a stable rate, the hormone provides contraception for 1-5 years, with the period of protection conferred dependent upon the specific progestin and type of polymer employed. Once inserted, the device allows a woman to have sexual intercourse over a certain period of time without any significant risk of becoming pregnant. Protection is ensured with a low drug dosage and no estrogen, and fertility is readily reversible once the implants are removed. The levonorgestrel implant Norplant R is the only subdermal contraceptive implant system approved for distribution. Annual pregnancy rates using Norplant are extremely low. Menstrual problems are the main reason why women discontinue using Norplant. Research is ongoing to reduce the number of implanted units and to introduce other progestins which may minimize side effects. Norplant-2 was designed to release the same dose of progestin from only two covered rods. Nestorone, 3-Keto-desogestrel, and Uniplant are single implants under development which are expected to be effective for 1-2 years. Completed phase II clinical trials with Nestorone found no pregnancies in 1570 woman-months of use, although bleeding irregularities occurred in 20-30% of women. A multicenter study is ongoing with a newly-designed 3-keto-desogestrel implant named Implanon, as well as another multicenter study with Uniplant, an implant which releases nomegestrol acetate with a one-year duration of action.

To study ovarian function, bleeding patterns, and side effects during the 1-year use of a new modified contraceptive subdermal implant releasing the progestin ST-1435 with a lifetime of 2 years.The effect on ovarian function and bleeding patterns of one contraceptive implant releasing the progestin ST-1435 was studied in 26 healthy women who volunteered. Side effects were recorded.The outpatient clinic of the City Maternity Hospital, Helsinki, Finland.One ST-1435 contraceptive implant was inserted subcutaneously into the ventral aspect of left upper arm.The women attended the clinic at half-year intervals. Records of bleeding were kept. Blood samples were collected from 5 women before insertion of an implant, from 12 women during the first 5 to 6 weeks of use, and from 10 women during the 6th and 12th month of use. Serum concentrations of ST-1435, progesterone, and estradiol were determined. Side effects were reported.The study covered 302 woman-months. The implant gave serum concentrations of ST-1435 high enough to inhibit ovulation in all of the 37 analyzed cycles. No pregnancies occurred. Irregular bleeding or spotting was the main event observed, especially during the 1st year of use. One half of the users had irregular cycles. None of the women's implants was removed during 1 year of use because of irregular bleeding. The implant was well accepted and tolerated by the women; no hormonal side effects were reported.One single 4-cm subdermal ST-1435 implant with a lifetime of 2 years showed good contraceptive efficacy and led to suppression of ovulation. No hormonal side effects were reported. Irregular bleeding patterns were common but well-tolerated, and the implant had a high continuation rate.Physicians inserted a new 4-cm subdermal implant releasing the progestin ST-1435 (78 mg) into the ventral area of the left upper arm in 26 healthy 20-36 year old women at the outpatient clinic at the City Maternity Hospital in Helsinki, Finland, and followed them for 12 months (total of 302 woman months) to examine its side effects, ovarian function, and bleeding patterns. (This implant has a lifetime of 2 years.) The implant released ST-1435 at serum levels high enough to suppress ovulation in all 37 analyzed menstrual cycles. None of the women became pregnant. Irregular bleeding occurred in 11 women. Even though a high proportion of women experienced irregular bleeding, it did not lead any women to request removal of the implant. The total spotting days decreased significantly between the first 6 months and the last 6 months (24-16 days; p .05). None of the women experience hormonally induced side effects, other than irregular bleeding. After 1 year of use, the continuation rate stood at 89%. 2 women wanted the implant removed so they could become pregnant. 1 woman wanted it removed for personal reasons. In conclusion, the women tolerated this implant well. Moreover, it was effective in preventing pregnancy.

To study the changes in serum lipids, serum chemistry, blood pressure, and body weight in long-term users of subcutaneous contraceptive implants releasing the progestin ST 1435.The study was done in the outpatient clinic of the City Maternity Hospital, Helsinki, Finland. Subdermal implants releasing the progestin ST 1435 were inserted in 30 women for 2 years of use. Healthy women aged 19-35 used the implants for contraception. Measurements of body weight and blood pressure were made and blood samples for lipid analysis (total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and triglycerides) and serum chemistry were taken before insertion of the implants and every 6 months thereafter until removal. Results are reported for 30 subjects after 6 months of use, 25 subjects after 12 months, 13 after 18 months, and 12 after 24 months.Blood pressure and serum chemistry, ie, liver enzymes and electrolytes, remained unchanged. Slight weight gain occurred, but was not statistically significant. No statistically significant changes were found in lipids or lipid ratios when comparing the values during use of the implant with the pre-treatment values.The progestin ST 1435, used parenterally for contraception or progestin therapy, had no adverse effects on serum lipids, blood pressure, or body weight, which are known to be risk factors for coronary artery disease. The steroid had no effects on serum chemistry determinations in long-term use.

Four different models of contraceptive vaginal rings were tested during three cycles for luteal activity, bleeding control, plasma lipoproteins and serum levels of the contraceptive steroids. Two progestins, levonorgestrel acetate (LNGA) and ST 1435, alone or in combination with ethynyl-estradiol (EE) were tested. The rings released 100 ug/day of the progestins and 30 ug/day of EE. Luteal activity was detected among users of the progestin-only rings: 4 of 8 cycles with ST 1435 and 2 of 10 with LNGA. Only one of the 18 cycles studied with the two combined rings showed luteal activity, but the measurement of contraceptive steroid in plasma suggested that this subject delayed reinsertion of the ring for about one week in that particular cycle. Breakthrough bleeding was observed in 12 of 30 cycles of use of the progestin-only rings, and in only 2 of 27 cycles with the combined models. No significant changes in total cholesterol or its HDL-fraction were observed. However, the only reduction observed in HDL-cholesterol was among users of the LNGA-only ring. It is concluded that the two combined CVR models offer good possibilities of high effectiveness and bleeding control and merit further development.Researchers analyzed data on 20 18-38 year old volunteers from the family planning clinic of PROFAMILIA in Santo Domingo, Dominican Republic, who had earlier undergone female sterilization to evaluate 4 different models of contraceptive vaginal rings during 3 cycles so as to identify which models would be the most likely to be an acceptable, safe, and effective family planning method. Women who used either of the 2 combined rings (ethinyl estradiol [EE] and either levonorgestrel acetate [LNGA] or ST 1435) had higher mean total serum levonorgestrel levels than those using the progestin-only rings (LNGA or ST 1435) (most were significant at .005). Luteal activity which marked ovulation was basically limited to users of the progestin-only rings (50% of cycles with ST 1435 and 20% of LNGA). It occurred in 1 of 18 cycles (5.6%) of users of combined rings (LNGA + EE). It probably occurred because of delayed insertion. The combined rings caused fewer incidents of breakthrough bleeding than did the progestin-only rings (7.4% vs. 40%). Neither the progestin-only nor the combined vaginal rings significantly altered total cholesterol or high density lipoprotein (HDL) levels. Users of the LNGA-only ring did experience an insignificant reduction in HDL, however. Further, triglycerides increased among users of the combined vaginal rings, but the increase was only significant with the LNGA + EE ring (25.4 mg/dl increase; p .05). Moreover, they fell significantly among users of the LNGA only ring (45.5 mg/dl decrease; p .05). The researchers concluded that the 2 combined rings hold the most promise due to good bleeding control and high effectiveness and therefore deserve further development.

Objective To study the endometrial effect of the transdermal synthetic progestin ST-1435. Design Prospective. Setting City Maternity Hospital, Helsinki, Finland. Patients Eleven postmenopausal women used transdermal estradiol (E 2 ) patches for 6weeks immediately before a vaginal operation for prolapse. For the last 10days, 1mg of ST-1435 transdermally in a gel was combined to the treatment. Main Outcome Measures Blood samples were taken to follow serum concentrations of E 2 , follicle-stimulating hormone, and ST-1435. Endometrial samples for histologic examination were collected during the operation to evaluate the effect of the progestin. Results Transdermal absorption of ST-1435 resulted in reasonably constant serum concentrations of ST-1435 in each subject. A progestin effect on the endometrium was seen in 9 of 10 samples obtained. One sample did not show any progestin effect in spite of adequate ST-1435 levels, but this patient's E 2 concentrations were low. Conclusions When the estrogen stimulation was adequate, the transdermal ST-1435 induced a progestin effect on the endometrium, i.e., it had an end-organ effect.