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Introduction: It is becoming more evident that hormone balance is not only vital to a healthy lifestyle, but necessary for health, vitality and longevity. Men and women alike suffer from [...]

Epithelial-specific activation of the PI3-kinase pathway is the most common genetic alteration in type I endometrial cancer. In the majority of these tumors, PTEN expression is lost in the epithelium but maintained in tumor stroma. Currently reported PTEN knockout mouse models initiate type I endometrial cancer concomitant with loss of PTEN in both uterine epithelium and stroma. Consequently, the biologic outcome of selectively activating the PI3-kinase pathway in the endometrial epithelium remains unknown. To address this question, we established a malleable in vivo endometrial regeneration system from dissociated murine uterine epithelium and stroma. Regenerated endometrial glands responded to pharmacologic variations in hormonal milieu similar to the native endometrium. Cell-autonomous activation of the PI3-kinase pathway via biallelic loss of PTEN or activation of AKT in adult uterine epithelia in this model was sufficient to initiate endometrial carcinoma. AKT-initiated tumors were serially transplantable, demonstrating permanent genetic changes in uterine epithelia. Immunohistochemistry confirmed loss of PTEN or activation of AKT in regenerated hyperplastic glands that were surrounded by wild-type stroma. We demonstrate that cell-autonomous activation of the PI3-kinase pathway is sufficient for the initiation of endometrial carcinoma in naive adult uterine epithelia. This in vivo model provides an ideal platform for testing the response of endometrial carcinoma to targeted therapy against this common genetic alteration. tissue regeneration model | progesterone receptor | uterine cancer doi/ 10.1073/pnas.1012548107

Cows induced to ovulate small dominant follicles were reported to have reduced pregnancy rates compared with cows that ovulated large follicles. The reason for the presence of small dominant follicles at the time of GnRH-induced ovulation in timed AI protocols is unknown. The objectives of this experiment were to examine the role of day of the estrous cycle at initiation of treatment on ovulation after the first GnRH injection (GnRH1) and associated effects on growth rate and final size of the ovulatory follicle at the second GnRH injection (GnRH2), serum concentrations of estradiol at GnRH2, and subsequent luteal concentrations of progesterone in suckled beef cows. Estrous cycles of cows were manipulated to be at 1 of 5 specific days of the cycle (d 2, 5, 9, 13, and 18, d 0 = estrus; n = 12 per treatment group) at the beginning of the CO-Synch protocol (GnRH1 on d -9, [PGF.sub.2[alpha]] on d -2, and GnRH2 on d 0). Day of the estrous cycle at GnRH1 did not affect the size of the preovulatory follicle or the proportion of cows ovulating at GnRH2 (P = 0.65 and 0.21, respectively). When all cows were included in the analysis, cows that ovulated after GnRH1 had similar follicle size at GnRH2 compared with cows that did not ovulate after GnRH1 (11.4 and 10.4 mm, respectively; P = 0.23). When only cows that could ovulate after GnRH1 (excluding cows treated on d 2) were included in the analysis, cows that ovulated to GnRH1 had a larger follicle at GnRH2 than cows that did not ovulate after GnRH1 (11.4 and 9.5 mm, respectively; P = 0.04). Follicle growth from d -5 to 0 was similar between cows that ovulated after GnRH1 and cows that did not (1.01 vs. 0.89 mm/d, respectively; P = 0.75). There was a tendency for faster follicle growth rate in cows that ovulated a large follicle (>11 mm) compared with cows that ovulated a small follicle ([less than or equal to]11 mm; 1.01 vs. 0.86 mm/d, respectively; P = 0.07). Serum concentrations of estradiol at GnRH2 and progesterone after ovulation were reduced in cows that ovulated small follicles compared with cows that ovulated large follicles (P = 0.006 and 0.005, respectively). In summary, day of the estrous cycle at initiation of synchronization did not affect ovulatory follicle size, but follicle growth rates affected the size of the follicle at GnRH2. Cows that ovulated a small follicle had reduced serum concentrations of estradiol at GnRH2 and progesterone after ovulation. Key words: beef cattle, estradiol, follicle diameter, follicle growth, ovulation rate, progesterone doi: 10.2527/jas.2009-2531

Steroids play fundamental roles regulating mammalian reproduction and development. Although sex steroids and their receptors are well characterized in vertebrates and several arthropod invertebrates, little is known about the hormones and receptors regulating reproduction in other invertebrate species. Evolutionary insights into ancient endocrine pathways can be gained by elucidating the hormones and receptors functioning in invertebrate reproduction. Using a combination of genomic analyses, receptor imaging, ligand identification, target elucidation, and exploration of function through receptor knockdown, we now show that comparable progesterone chemoreception exists in the invertebrate monogonont rotifer Brachionus manjavacas, suggesting an ancient origin of the signal transduction systems commonly associated with the development and integration of sexual behavior in mammals. receptor | imaging steroids doi/ 10.1073/pnas.1006074107

The association of the 2464G > A SNP found in the promoter region of the rabbit progesterone receptor gene with progesterone receptor (PR) expression was evaluated by Western blot analysis. This SNP was associated with 2 lines divergently selected for uterine capacity, the high line selected to increase uterine capacity and the low line selected to decrease uterine capacity. Two progesterone isoforms were obtained using a commercial monoclonal antibody: the PR-B isoform described previously in rabbits, and the PR-A isoform, not described previously in rabbits. The GG genotype, the genotype more frequent in the high line, showed less PR-B and PR-A expression than the AA genotype in the oviduct (GG/[AA.sub.PR-B] = 0.81 and GG/[AA.sub.PR-A] = 0.73) and uterus (around 0.70 in both isoforms). The GA genotype showed similar PR-A expression in both tissues and also similar PR-B expression in the oviduct to the GG genotype. Conversely, the GG genotype showed less PR-B expression than the GA genotype in the uterus (GG/[GA.sub.PR-B] = 0.79). Similar expression of both PR isoforms was found in the uterus at d 2 and 3 of gestation; meanwhile, an increase of both isoforms was observed in the oviduct. Similar PR-A expression was observed in the ampulla and isthmus; meanwhile, the PR-B expression in the isthmus was double that in the ampulla. Key words: oviduct, PGR genotype, progesterone receptor expression, rabbit, uterus doi: 10.2527/jas.2009-1955

Progesterone (P4) inhibits the gastrointestinal muscle contraction by downregulating [G[alpha].sub.q/11] proteins that mediate contraction, by upregulating [G[alpha].sub.s] proteins that mediate relaxation, and by altering the pattern of cyclooxygenase (COX) enzymes and prostaglandins. We aimed to examine whether P4 treatment of guinea pigs in vivo affects basal colon motility [basal motility index (MI)] by altering the levels and actions of [PGF.sub.2[alpha]] and[ PGE.sub.2]. Guinea pigs were treated with intramuscular (IM) P4 for 4 days. The BASAL MI, the [PGF.sub.2[alpha]]-induced contraction, and PGE2-induced inhibition of contraction were examined in muscle strips and cells. The levels of [PGF.sub.2[alpha]] and [PGE.sub.2] were measured by radioimmunoassay. Treatment with P4 reduced the basal MI, the levels of [PGF.sub.2[alpha], and [PGF.sub.2[alpha]]-induced contraction. P4 increased [PGE.sub.2] levels, and [PGE.sub.2] induced relaxation. Pretreatment with IM RU-486 (10 mg/kg per day), a P4 receptor antagonist, 1 h before P4 blocked the actions of P4. The [PGF.sub.2[alpha]] antagonist A1-1180 abolished basal MI and [PGF.sub.2[alpha]]-induced contraction. N-ethylmaleimide, which blocks unoccupied membrane receptors, blocked Ach and VIP actions but had no effect on [PGF.sub.2[alpha]] and [PGE.sub.2] effects. A COX-1 inhibitor decreased and a COX-2 inhibitor increased [PGF.sub.2[alpha]] levels; GTP[gamma]S increased and GDP[beta]S decreased the levels of [PGF.sub.2[alpha]]. [G[alpha].sub.q/11] protein antibodies (Abs) reduced [PGF.sub.2[alpha]] levels, and [G[alpha].sub.i3] Abs blocked its motor actions. G[alpha]s Abs increased [PGF.sub.2[alpha]] but decreased [PGE.sub.2] levels. We concluded that P4 decreases basal MI by reducing [PGF.sub.2[alpha]] levels caused by downregulation of [G[alpha].sub.q/11] and that [PGF.sub.2[alpha]]-induced contraction was blocked by downregulating [G[alpha].sub.i3]. P4 also decreased the basal MI by increasing [PGE.sub.2] levels, and [PGE.sub.2] induced relaxation by upregulating [G[alpha].sub.s] proteins. colon motility; guinea pigs; [PGF.sub.2[alpha]]; [PGE.sub.2]; G proteins doi: 10.1152/ajpgi.00184.2009.

Gallbladder disease is prevalent during pregnancy. It has been suggested that this complication of pregnancy is attributable to increased bile cholesterol (Ch) induced by estrogens and to gallbladder hypomotility caused by increasing levels of progesterone (P4). Studies on nonpregnant gallbladders have shown that increased levels of bile Ch contribute to both gallstone formation and bile stasis. These studies investigated the effects of high levels of plasma membrane Ch on P4 on gallbladder muscle cells from human and guinea pigs. Contraction was studied in intact and permeabilized muscle cells. G proteins were determined by Western blot, and [sup.3]H-P4 incorporation by muscle cells was measured in the [beta]-scintillation counter. High levels of caveolar Ch blocked the effects induced by P4 treatment for 6 h. They suppressed the expected P4 inhibition of GTP-[gamma]S (a G protein activator)-induced contraction and changes in G proteins by downregulating Gi3 and upregulating Gs protein levels. Ch inhibited these P4 actions at the caveolar 3 (CAV-3) level, since the P4 effects were antagonized by treatment with CAV-3 antibody, by reducing CAV-3 expression through CAV-3 siRNA. CAV-3 antibody and siRNA reduced caveolar Ch levels. High caveolar levels of Ch and CAV-3 antibody blocked the incorporation of [sup.3]H-P4 into caveolae. Treatment with GDP-[beta]S (a G protein antagonist) had no effect on P4 actions. High caveolar Ch levels blocked the P4 effects on muscle contraction and G protein changes probably because both Ch and P4 require CAV-3 proteins for their transport across the plasma membrane. muscle cells; caveolar 3 proteins; G proteins

The performance of an antiserum to progesterone and pregnane neurosteroids was assessed in two competitive assay setups: radioimmunoassay and enzyme-linked immunoassay with colorimetric detection, both with the same limit of detection of 2 pg. The enzyme-linked immunoassay was less labor-intensive and had better precision of measurement and was used to measure progesterone and six of its ring A-reduced metabolites in rat plasma. The measured levels of allopregnanolone and progesterone were in agreement with those reported previously when measured by gas chromatography/mass spectrometry and high-performance liquid chromatography coupled with radioimmunoassay and substantially lower than those previously measured by radioimmunoassay without chromatographic separation. Both isomers of dihydroprogesterone and all four isomers of pregnanolone were detected in rat plasma, indicating that progesterone is metabolized by reduction at the C5 and C3 position of the A ring, in both [alpha] and [beta] configurations. In addition to 5[beta]-dihydroprogesterone and isopregnanolone, which have not been previously detected in the rat, we found considerable amounts of pregnanolone, which is neuroactive, with similar potency to that of allopregnanolone but was previously thought not to be produced in rats.

Colon muscle strips and cells from female patients with slow-transit constipation (STC) exhibit impaired motility, signal transduction abnormalities characterized by downregulation of [G.sub.q/11] and upregulation of [G.sub.s] proteins, decreased cyclooxygenase (COX)-1 and thromboxane (Tx)[B.sub.2] levels, increased COX-2 and [PGE.sub.2] levels, and overexpression of progesterone receptors (PGR). Progesterone ([P.sub.4]) treatment of normal cells reproduced these motility and signal transduction abnormalities. The purpose of the study was to examine whether overexpression of PGR-B reproduces these abnormalities by rendering the cells more sensitive to physiological concentrations of [P.sub.4]. Cultured human colon muscle was transfected with a plasmid DNA expressing PGR-B. The mRNAs of PGR, COX-l, COX-2, and [G.sub.q/11] were determined by quantitative real-time PCR. Their protein expression was determined by Western blot, and prostaglandins were measured by radioimmunoassay. Cultured muscle cells maintained their phenotypic features determined with myosin light chain (MLC) and h-caldesmon antibodies. Control and transfected muscle cells responded to [10.sup.-6] M [P.sub.4]. In contrast, muscle cells transfected with PGR-B responded to lower [P.sub.4] concentration ([10.sup.-7] M). This [P.sub.4] concentration reduced MLC phosphorylation induced by CCK-8 ([10.sup.-8] M), downregulated [G.sub.q/11], and decreased COX-1 and Tx[B.sub.2] levels. It upregulated [G.sub.s] proteins. It also increased COX-2 and [PGE.sub.2] levels. We conclude that overexpression of PGR-B renders the cells more sensitive to physiological concentrations of [P.sub.4]. These results are consistent with the hypothesis that overexpression of PGR-B contributes to the motility and signal transduction abnormalities observed in female patients with STC and normal serum levels of [P.sub.4]. G proteins; cyclooxygenase enzymes; prostaglandins

TNF is well known for its role in inflammation, including direct effects on the vasculature. TNF also is implicated in the regulation of reproduction by its actions to affect ovarian steroidogenic cells and to induce apoptosis of corpus luteum (CL)-derived endothelial cells in vitro. We hypothesized that the disruption of TNF signaling would postpone the regression of the highly vascularized CL in vivo, and this effect could be replicated in mutant mouse models lacking TNF receptor ([TNFRI.sup.-/-)] and/or a critical enzyme of TNF signaling, acid sphingomyelinase ([ASMase.sup.-/-).] In the current study, the treatment of pseudopregnant mice with the luteolytic mediator prostaglandin F2-[alpha] (PGF) significantly increased TNF in the ovaries when compared with saline-treated controls. Treatment with PGF also reduced serum progesterone (P4) concentrations and caused involution of the CL. However, pretreatment of pseudopregnant mice with Etanercept (ETA), a TNF-neutralizing antibody, inhibited the PGF-induced decrease in P4 and delayed luteal regression. A similar outcome was evident in pseudopregnant [TNFRI.sup.-/-] animals. Treatment of luteal microvascular endothelial cells (MVECs) with TNF provoked a significant increase in ASMase activity when compared with the corresponding controls. Furthermore, TNF-induced MVEC death was inhibited in the [ASMase.sup.-/-] mice. The [ASMase.sup.-/-] mice displayed no obvious evidence of luteal regression 24 h after treatment with PGF and were resistant to the PGF-induced decrease in P4. Together these data provide evidence that TNF plays an active role in luteolysis. Further studies are required to determine the deleterious effects of anti-inflammatory agents on basic ovarian processes. corpus luteum | cytokines | endothelial cells | ovary | progesterone

C-reactive protein (CRP) is a widely used, sensitive biomarker of inflammation. Studies conducted among users of exogenous hormones suggest that estrogen increases CRP, whereas progesterone decreases CRP. Examinations of CRP in normally cycling women suggest the opposite: CRP is negatively associated with endogenous estrogen and positively associated with endogenous progesterone. This work evaluates the association between menstrual cycle-related hormone changes and events (menstruation and ovulation) and CRP. Eight female subjects gave urine and blood samples from twelve days across the menstrual cycle, for a total of eleven cycles. Blood samples were assayed for CRP; urine samples for [beta]-follicle stimulating hormone [beta]FSH), pregnanediol 3-glucuronide (PDG), and estrone glucuronide (E1G). Ovulation day was estimated using hormone levels. Presence or absence of menses was reported by subjects. Analyses were conducted with random-effects linear regression. All cycles were ovulatory; day of ovulation was identified for nine cycles. A ten-fold increase in progesterone was associated with a 23% increase in CRP (P = 0.01), a ten-fold increase in estrogen was associated with a 29% decrease in CRP (P = 0.05), and menses was associated with a 17% increase in CRP (P = 0.18); no association between ovulation or FSH and CRP was found. Hormone changes across the menstrual cycle should be controlled for in future studies of inflammation in reproductive-age women. KEY WORDS inflammation; estrogen; progesterone; biomarker

There are two major subtypes of human breast cancers: the luminal, estrogen, and progesterone receptor-positive, cytokeratin 18-positive (E[R.sup+]P[R.sup+]CK[18.sup+]) subtype, and the basal E[R.sup-]P[R.sup-]CK[18.sup-]CK[5.sup+] subtype. Tumor-initiating cells (CD[44.sup+]) have been described for human breast cancers; whether these are common to the two subtypes is unknown. We have identified a rare population of cells that are both CD[44.sup+] and E[R.sup-]P[R.sup-]CK[5.sup+] in luminal-like E[R.sup+]P[R.sup+] T47D human breast tumor xenografts. The tumor-isolated CD[44.sup+] cell fraction was highly enriched for clonogenic (in vitro culture) and tumorigenic (in vivo reimplantation) cells compared with the CD[44.sup-] cell fraction. Rare E[R.sup-]P[R.sup-]CK[5.sup+] cells were present within CD[44.sup+]-derived colonies. Tumor-isolated cells placed in minimal media also contained rare E[R.sup-]P[R.sup-] CK[5.sup+] cells at early time points ( cancer stem cell | cytokeratin 5 | estrogen receptor | progesterone receptor

August-Copenhagen-Irish (ACI) rats are unique in that the ovaryintact females develop high incidence of mammary cancers induced solely by hormones upon prolonged exposure to high levels of estrogen alone. Studies have also shown that such prolonged exposure to high-dose estrogen results in human-like aneuploid mammary cancers in ovary-intact ACI rats. To determine the role of progesterone in mammary carcinogenesis, six-week-old intact and ovariectomized ACI rats were continuously exposed to low- and high-dose estrogen alone, progesterone alone, low-dose estrogen plus progesterone, and ovariectomized ACI rats with high-dose estrogen plus progesterone. Also, ovariectomized ACI rats were treated with high-dose estrogen plus progesterone plus testosterone to determine the role of the androgen, testosterone, if any, in hormonal mammary carcinogenesis. The results indicate that continuous exposure to high, but not low, concentrations of estrogen alone can induce mammary carcinogenesis in intact but not in ovariectomized rats. Mammary carcinogenesis in ovariectomized ACI rats requires continuous exposure to high concentrations of estrogen and progesterone. The addition of testosterone propionate does not affect tumor incidence in such rats. These results suggest that both ovarian hormones estrogen and progesterone are necessary for mammary carcinogenesis induced solely by hormones in ovariectomized ACI rats. Our results are in agreement with the Women's Health Initiative studies, where treatment of postmenopausal women with estrogen (ERT) alone did not increase the risk of breast cancer, but estrogen and progesterone (HRT) did.

Progesterone and estrogens play key roles in regulating various physiological phenomena related to normal growth, development, and reproduction of domestic animals. This review focuses on the mechanisms by which progesterone and estrogens regulate the reproductive processes in these animals. The majority of research on the actions of progesterone and estrogens on the reproductive systems of cattle, sheep, and pigs has been genomic in nature and represents attempts to better understand how these steroids regulate gene expression. Results of recent research suggest that progesterone and estrogens can alter target cell responses nongenomically via membrane receptors. The characteristics of membrane receptors for progesterone and estrogen in various cell types are described and the intracellular signal pathways defined. Estrogens acting via membrane receptors can suppress LH secretion by gonadotropes and stimulate rapid increases in uterine blood flow. Progesterone acting via a membrane receptor has been shown to inhibit binding of oxytocin to oxytocin receptors in isolated endometrial plasma membranes and stimulate capacitation of spermatozoa. Results of research suggest that progesterone and estrogens can act nongenomically to alter target cell responses in domestic animals. The biological implications of this mode of action in these animals are discussed. Key words: estradiol-17[beta], luteinizing hormone, membrane receptor, oxytocin, progesterone, uterus

Progesterone is an important reproductive hormone and measurement of its level by repeated blood samplings is beneficial to monitoring of estrus cycle. However, since toy poodles have a small body size and thin-walled blood vessels, repeated blood samplings cause stress and affect their preparation for mating or artificial insemination (AI). Therefore, a noninvasive method for monitoring progesterone concentration should be developed. Here, we show that time-resolved fluoroimmunoassay (TF-RIA) is a useful noninvasive method for determining the progesterone concentration in serum and fecal samples obtained from toy poodles. Present results demonstrate that progesterone concentrations in the fecal correlated with the serum collected in same time and the sequential changes in progesterone concentrations in the feces are paralleled in the serum. Therefore, this technique may be suitable for monitoring the estrus cycle in toy poodles. Key words: Fecal, Progesterone concentration, Time-resolved fluoroimmunoassay, Toy poodle, INTRODUCTION Progesterone is a hormone that controls many aspects of reproduction in female mammals, such as preparation of the endometrium for embryo implantation, maintenance of pregnancy, gonadotropin secretion and sexual [...]

Intravaginal impedance (IVI) fluctuates during the goat estrous cycle. To understand which ovarian steroids are responsible for IVI changes and whether IVI variations are associated with precopulatory and copulatory behaviors, 8 ovariectomized females were assigned to 4 treatments in a 4 x 4 Latin square replicated over four 8-d periods. The treatments were as follows: progesterone plus estradiol-17[beta] ([P.sub.4] + [E.sub.2]), oil plus estradiol-17[beta] ([E.sub.2]), progesterone plus oil (P.sub.4]), or oil (OIL). Daily IVI measurements at the vaginocervical junction were taken at 1 and 70 KHz. Progesterone was given on d 2 and 3. Estradiol was given in the evening of d 5. On d 1 to 8, goats were group-exposed to a sexually experienced male and observed for the expression of sexual behaviors. On d 6 and 7, IVI was less when goats received [P.sub.4] + [E.sub.2] or [E.sub.2] compared with goats given [P.sub.4] or OIL (P < 0.05). Impedance measured at 1 kHz tended to remain lower on d 8 in [P.sub.4] + [E.sub.2] treated females compared with those given [P.sub.4] or OIL (P < 0.055). Like previous results, [P.sub.4] + [E.sub.2] or [E.sub.2] treatment induced behavioral estrus; 5 of 8 [P.sub.4] + [E.sub.2]-treated and 5 of 8 [E.sub.2]-treated females were sexually receptive on d 6. On d 7, although IVI remained low and 2 of 8 [P.sub.4] + [E.sub.2]-treated goats and 4 of 8 [E.sub.2]-treated goats remained sexually receptive, no additional females were in estrus. No IVI decreases and no estrous behavior were observed in goats given [P.sub.4] or OIL. This experiment demonstrated that E2 initiates the periestrous drop in IVI, and [P.sub.4] may delay baseline return. Key words: estrogen, estrus, goat, impedance, progesterone, vagina

Population performance of white-tailed deer (Odocoileus virginianus) is driven largely by survival and reproduction. Knowledge of age-specific reproduction would enhance our understanding of population performance and dynamics relative to intrinsic factors, regulatory mechanisms, and their interaction with extrinsic factors. From 1991 to 2002, we examined serum progesterone as an indicator of pregnancy in free-ranging white-tailed deer (0.5-15.5 years old), age-specific fertility and fecundity, and the potential effect of reproductive senescence on population change. We did not detect relationships between serum progesterone concentrations and Julian date, age, or body mass at capture in 41 confirmed-pregnant, adult ([greater than or equal to] 1.0-year-old) does. Serum progesterone concentrations of 284 females ranging in age from 0.5 to 15.5 years were distributed bimodally with a narrow peak at 0.04-0.4 ng/ml (composed of samples from 46 of 50 fawns) and a broad peak centered at about 3.6 ng/ml. Only 1 (1.8%) of 55 fawns was pregnant, whereas pregnancy rates were 96.6% (112 of 116) for 2.5-7.5 year olds and 98.5% (64 of 65) for 8.5-15.5 year olds. Among adults, the lowest pregnancy rates occurred in yearlings (87.5%), not in the oldest does. Mean estimated fecundity was 1.3 fetuses per doe in yearlings and was 1.8 fetuses per doe in 2.5-15.5 year olds. We observed no evidence of senescence relative to fertility and fecundity in adult female white-tailed deer up to 15.5 years old. Because older does comprise a relatively small proportion of the population, fecundity rates of these females have little impact on population change ([lambda]); however, their ultimate value to the population may be in their life-long reproductive success and associated genetic contribution. Key words: age-specific fertility, fecundity, Odocoileus virginianus, pregnancy, reproduction, senescence, white-tailed deer