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3 beta-Hydroxysteroid isomerase dehydrogenase, capable of acting on C21- and C19-3 beta-hydroxy-5-ene-steroids has been found in guinea-pig kidney at equivalent levels to those in guinea pig testes. Of the 3 beta-hydroxy-5-ene-steroids present in guinea pig serum, 21-hydroxypregnenolone occurs in highest concentration (17 nM) followed by pregnenolone (10 nM), whereas 17 alpha-hydroxy-pregnenolone and dehydroepiandrosterone occur in very low concentrations (less than 0.5 nM). Furthermore, the concentration of 21-hydroxypregnenolone relative to 11-deoxycorticosterone (the mineralocorticoid of the guinea pig), is 10:1 (Nishikawa and Strott, Steroids 41 (1983) 105-120). The apparent Km value for 21-hydroxypregnenolone, for the reaction yielding 11-deoxycorticosterone as catalysed by guinea pig kidney microsomes, was 85 nM and the Vmax 33 pmol/min per mg protein. Pregnenolone was a competitive inhibitor (apparent Ki = 5 microM) in the above reaction. A sex difference in the level of the enzyme in the kidney was found (activity in the female was one-third of that in the male) which may indicate that the enzyme is under partial androgen control. 3 beta-Hydroxysteroid isomerase dehydrogenase activity was also detected in guinea pig liver and again it was lower in the female. Whilst the exact role of 3 beta-hydroxysteroid isomerase dehydrogenase in guinea-pig kidney remains uncertain, the data suggest that it may utilise blood-borne 21-hydroxypregnenolone, the later then playing the role of a prohormone.

Long-chain fatty acid esters of the adrenal-derived estrogen 5-androstene-3 beta, 17 beta-diol (ADIOL) were found to accumulate in four human mammary cancer cell lines (MCF-7, ZR-75-1, MDA-MB-231 and MDA-MB-330) when explosed to 10-30 nM ADIOL for variable time periods. At each time point examined, the monoester fraction, which represented the major component of the total lipoidal fraction, contained fatty acids linked to either the 3 beta- or 17 beta-positions. However, there was considerable variation in the ratio of 3 beta- to 17 beta-monoesters in the four cell lines. By means of reverse phase HPLC and referral to authentic synthesized compounds, each monoester fraction was found to contain a number of long-chain fatty acid components whose composition resembled that previously determined for the fatty acid esters formed from 17 beta-estradiol. A specific and measurable turnover of a subfraction of ADIOL-17 beta-monoesters composed of essential fatty acids (22:6, 20:4, 18:3) occurred in MCF-7 cells, and to a lesser extent in ZR-75-1 cells. No changes were observed with time in any of the components of the 3 beta- or 17 beta-monoester fractions in MDA-MB-231 and MDA-MB-330 cells. These results, coupled with other studies, now suggest that a very rapid turnover of some components of these lipoidal derivatives may be occurring. If so, it is possible that the system of acylation-deacylation may be involved in a transport mechanism for estrogens and perhaps other steroid hormones.

Microsomal preparations derived from bovine placenta cotyledons, previously investigated as a convenient source of fatty acyl coenzyme A: estradiol-17 beta-acyl transferase, have been shown to acylate other steroids bearing 3 beta- or 17 beta-hydroxyl groups. In the presence of 0.1 mM oleoyl CoA, the apparent Km values for dehydroepiandrosterone, testosterone, and 5-androstene-3 beta,17 beta-diol (delta 5-DIOL) were 45, 67, and 20 microM, respectively. Acylation of delta 5-DIOL occurred at either the 3 beta- or 17 beta-positions to give monoesters. Testosterone, estradiol-17 beta, and delta 5-DIOL acted as competitive inhibitors for the acylation of the 3 beta-hydroxyl group of dehydroepiandrosterone (Ki values 71, 75, and 41 microM, respectively). Such data indicate that a single enzyme of wide substrate specificity may be involved in these acylation reactions. When estrogen receptor (ER) positive and negative human mammary cancer cell lines were incubated with 10 nM [3H]delta 5-DIOL, intracellular accumulation of delta 5-DIOL long-chain fatty acid esters occurred; rates being higher (p less than 0.001) in ER negative cells (MDA-MB-231 and MDA-MB-330) compared to MCF-7 cells (ER positive), and higher (P less than 0.005) in MDA-MB-231 cells compared to ZR-75-1 cells (ER positive). After exposure to 10 nM [3H]delta 5-DIOL for 16 h, the total labeled steroid fatty acid fraction was composed predominantly of delta 5-DIOL-3 beta- and 17 beta-monoesters (approximately 85%), the remainder containing approximately equal amounts of delta 5-DIOL-diesters and dehydroepiandrosterone-3 beta-esters. Subsequent transfer to medium lacking delta 5-DIOL was accompanied by a breakdown of the labeled esters, which was more rapid in the ER positive cell lines. During this period, intracellular free delta 5-DIOL levels rapidly declined in MDA-MB-330 cells but were maintained in MCF-7 cells, presumably by binding to ER. This behavior parallels that of estradiol-17 beta previously observed in these cell lines and further emphasizes the potential importance of the adrenal-derived estrogen delta 5-DIOL in consideration of a hormone-based etiology of human breast cancer.

The quality of primary medical care was assessed by studying the events leading to 686 emergency admissions of patients from our hospital-based primary care practice. Independent physician reviewers determined that 59 (9 percent) of the admissions were potentially preventable; 40 were due to iatrogenic factors including inadequate follow-up and adverse drug reactions, 12 were due to lack of patient compliance, and seven were due to both iatrogenesis and noncompliance. Adverse drug reactions were the most common cause of iatrogenesis, and warfarin was the drug that most commonly caused an adverse reaction. Inadequate follow-up of abnormal physical findings, symptoms, and laboratory test results was also important. Patients with preventable admissions had more medical diagnoses (4.9 versus 4.1, p less than 0.01), were prescribed more medications (4.5 versus 3.7, p less than 0.01), and were older (66.5 years versus 60.2 years, p less than 0.01) than patients whose admissions were not preventable. It is concluded that a small percentage of emergency hospitalizations may be preventable and that systematic review of emergency hospitalizations may provide a means of measuring the quality of primary medical care.

A retrospective descriptive analysis was undertaken on all patients discharged from Ashburn Hall over a 14 month period. The sample of 256 patients was found to have a female to male ratio of 6:4 and contained 4.3% of individuals without school certificate (cf 48.3% national statistics) and 23% with a university degree or diploma (cf 13.2% in the general population). Seventy-four point six percent of the sample had some significant previous psychiatric history although for 68% of the sample this was their first admission to Ashburn Hall. A quarter of the sample came from the surrounding geographic area and patients were more likely to be referred by specialists rather than general practitioners as geographic distance increased from the hospital. Comparisons with the public system showed a predominance of patients with major affective disorder and less patients with a diagnosis of substance abuse and mental retardation.

The likely occurrence of two distinct types of human breast cancer is discussed. In the development of the "Western-environmental" or "adrenal" type, it is proposed that dehydroepiandrosterone sulphate (DHEAS), secreted by the adrenal, may be implicated. This steroid is metabolized by mammary tumors to active androgens and estrogens. That these metabolic pathways are very similar to that in skin is emphasized and this is possibly explained by evolution of the mammary gland from primitive sweat glands. Formation of DHEAS from DHEA in mammary tumors, claimed to be correlated with an individual subject's prognosis and response to hormone ablation, is discussed in the light of a possible regulatory role of the sulphotransferase. It is proposed furthermore that a specific control of DHEAS secretion in the adrenal may exist at the level of the sulphurylation step. Nutritional factors are also possibly implicated here and these are discussed in the light of: 1) a possible higher secretion rate of DHEAS in obese subjects; and 2) the low breast cancer incidence in the Japanese and the accompanying low blood DHEAS levels.

We conducted a case-control study of cigarette smoking and dysplasia and carcinoma in situ of the uterine cervix. Cases were black women 17 to 55 years of age who were attending a dysplasia clinic and had biopsy-confirmed cervical pathologic conditions. Controls were women who were attending the family planning clinic at the same hospital and who had at least two normal Papanicolaou smears. Results were adjusted for age, number of sexual partners, age at first intercourse, socioeconomic status, and oral contraceptive use. Cigarette smoking was significantly associated with carcinoma in situ, severe dysplasia, and mild-moderate dysplasia (relative risks, 3.6, 3.3, and 2.4, respectively). Cumulative exposure to cigarette smoking (as measured by pack-years smoked) was strongly related to the risk of these conditions; women with 12 or more pack-years of exposure had relative risks of 12.7, 10.2, and 4.3, respectively, for the three conditions. There was some evidence that the risk was greatest in women who began smoking in their early teenage years. A reduction in the risk of cervical cancer appears to be another inducement for young women not to smoke.

Long-chain fatty acid esters of 17 beta-estradiol and other steroid hormones, which are formed in hormone-sensitive tissues, can be regenerated to the free hormone by the action of an esterase present in the cytosol. This esterase has now been examined in bovine placenta cotyledons. Activity towards steroid fatty acid esters was accompanied by activity towards a diacylglycerol analogue and cholesteryl oleate. During purification procedures, the ratio of activities towards the diacylglycerol analogue and estradiol 17 beta-oleate remained approximately constant. Activity towards these two substrates was inhibited by increasing concentrations of HgCl2 and phenylmethanesulfonyl fluoride in a parallel manner. Upon treatment with [3H]diisopropyl fluorophosphate, a major labelled species of Mr approx. 84,000 was formed. Activation by ATP and the catalytic subunit of cAMP-dependent protein kinase occurred. These properties were very similar to those of the hormone-sensitive lipase of bovine adipose tissue previously reported and run in parallel in this study. A highly purified preparation of this latter enzyme was found to hydrolyse steroid fatty acid esters and relative activities towards such substrates, diacylglycerol analogue and cholesteryl oleate, were similar to the placenta esterase. When the two esterases were phosphorylated with [gamma-32P]ATP, a labelled species of Mr 84,000 was isolated in both cases by use of an antibody raised against purified hormone-sensitive lipase of bovine adipose tissue. It is concluded that hormone-sensitive lipase is very likely the enzyme responsible for hydrolysis of steroid fatty acid esters in bovine placenta and possibly steroid hormone target tissues in general.

Pure hydroxysteroid sulfotransferase (EC 2.8.2.2) of human adrenal glands possesses a wide substrate specificity towards steroids. This wide specificity has now been found to extend to simple alcohols; normal aliphatic alcohols from C3 onwards acting as substrates with C9 showing the highest rate. Increased rate was accompanied by a decrease in Km. In marked contrast to the sulfurylation of steroids such as dehydroepiandrosterone, which exhibit wave-like kinetics, the kinetics with simple alcohols were of the normal Michaelis-Menten type. By means of enzyme antibody and enzyme stability studies evidence was provided that one and the same enzyme was responsible for sulfurylation of hydroxyls on the 3- and 17- positions of steroids and simple alcohols. The data lend support to previous evidence that the enzyme controls the secretion of dehydroepiandrosterone sulfate via steroid-specific binding sites, enabling self-regulation in response to ACTH action.

Pure steroid alcohol sulphotransferase (EC 2.8.2.-) has the property of sulphurylating hydroxyl groups on different positions of the steroid ring. It has now been established that although only monosulphates are formed from substrates such as 3,17-diols, the position of the sulphate group depends on the relative configuration of the hydroxyl groups. Androst-5-ene-3 beta,17 beta-diol, for example, is sulphurylated mainly at the 17-position. In addition, compounds such as epitestosterone and 17 alpha-estradiol are sulphurylated at much higher rates than their respective 17 beta-epimers. It is believed that the steroid can approach the sulphurylation site via (i) ring A with the beta-side upwards, and in this mode a 3 beta-hydroxyl is sulphurylated at a higher rate than a 3 alpha-hydroxyl, or (ii) ring D with the beta-side downwards, and in this mode a 17 alpha-hydroxyl group is oriented in an analogous fashion to the 3 beta-hydroxyl in (i). The enzyme exhibits non-Michaelis-Menten kinetics within physiological concentrations (0-2 micro M) of the substrate dehydroepiandrosterone and evidence was obtained for the presence of multiple interacting steroid-binding sites. A regulatory role for the enzyme in the secretion of dehydroepiandrosterone from the human adrenal gland is proposed.

An entirely computerized ambulatory medical record system is operational in a large health maintenance organization. A unique subsystem was designed for use in prenatal care, in which the provider's completion of a single encounter form at the time of visit meets all the information requirements of care delivery, administration, and quality assurance. Instead of using a conventional paper chart, computer-generated summaries and flow charts are automatically provided for scheduled visits and for use as a hospital preadmission record, significantly reducing the provider effort expended on record keeping. On-line inquiry function is also available using terminals at the ambulatory center and the hospital. The computer data base has been used for quality assurance studies in prenatal care. The system is well accepted by providers, is reliable, and is cost effective.

Formation of lipoidal derivatives of estradiol-17 beta (E2) esterified to long-chained fatty acids has been reported to occur in estrogen target tissues. Employing human breast cancer cells in culture, we have detected the rapid synthesis of such compounds upon exposure of the cells to concentrations of [3H]E2 as low as 1 nM. When exposed to 10 nM [3H]E2 in the culture medium, synthesis of E2-lipoidal derivative (E2-L) reached 270 fmol/mg DNA in 2 h in the estrogen receptor positive MCF-7 human mammary cancer cell line. Higher rates (approximately 900 fmol/mg DNA in 2 h) were reached in 2 estrogen receptor negative human mammary cancer cell lines; MDA-MB-231 and MDA-MB-330. E2-L was the major form of estrogen in the latter cells at this time interval (E2-L/E2 approximately 3.0). Far higher concentrations of E2 were found in MCF-7 cells compared to 231 and 330 cells, and, in contrast to the latter, this was mostly specifically bound. Upon subsequent withdrawal of E2 from the medium, intracellular concentrations of E2-L decreased very rapidly in the first 5 h period, then declined more slowly to approximately 50 fmol/mg DNA at 24 h. Intracellular concentrations of E2 were maintained over this time period. E2-L was not present in the medium. Thus, accumulation of E2-L in cells upon continuous exposure to E2 represents the net result of esterification and deesterification reactions. These hydrophobic E2-derivatives may then be involved in the "capture" of E2 for transport through membranes and subsequent regeneration of E2 to maintain occupancy of the nuclear receptor.

Human primary mammary tumors were examined to determine what factors were of importance in deciding relative rates of sulfurylation of dehydroepiandrosterone and 17beta-estradiol, such rates having been shown to correlate with the patient's prognosis and response to adrenalectomy (T. L. Dao and P.R. Libby. Enzymic Synthesis of Steroid Sulfate by Mammary Cancer and Its Clinical Implications. Natl. Cancer Inst. Monographs, 34: 205-210, 1971). The sulfurylation of dehydroepiandrosterone and 17beta-estradiol was studied in 41 tumors in vitro using tumor cytosol, adenosine triphosphate, [35S]SO42-, Mg2+, and added steroid. Six tumors showed no sulfurylating ability, 9 sulfurylated dehydroepiandrosterone at a rate greater than that for 17beta-estradiol (ratio, greater than 1), and 26 sulfurylated dehydroepiandrosterone at a rate lower than that for 17beta-estradiol (ratio, less than 1). Evidence was obtained that low levels of dehydroepiandrosterone sulfotransferase were responsible for ratios of less than 1, in many instances. Adenosine 3'-phosphate 5'-phosphosulfate synthesis and steroid sulfotransferase activities were measured in 30 tumors. A significant correlation was found between synthesis of the former and levels of estrogen sulfotransferase, but this relationship did not hold for dehydroepiandrosterone sulfotransferase, again due to low levels of this enzyme in many tumors. It is suggested that dehydroepiandrosterone sulfate formation in the tumors is mainly controlled by the sulfotransferase, which acts as a shunt in regulating the level of free dehydroepiandrosterone, and related compounds, available for metabolism to steroids influencing the growth of mammary epithelial cells.

The formation of glucuronides of estradiol-17 beta by human mammary cancer cell lines is reported for the first time. When incubated with [3H]estradiol-17 beta (1 nM) for 16 h, ZR-75-1 and T47-D cells formed estradiol-3-glucuronide and estradiol-17 beta-glucuronide in approximately equal proportions, whereas MCF-7 cells formed E2-3-glucuronide only. Yields of monoglucuronides from MCF-7 and ZR-75-1 cells were 0.35 pmol/mg DNA, which represented 20-26% of the yield of estradiol-monosulphates. A HPLC system capable of separating most estradiol monosulphates, monoglucuronides and mixed conjugates, is described.

Dehydroepiandrosterone sulfate is the major secretory product of the human adrenal cortex. The enzyme responsible for the sulfurylation, which has been isolated previously, possesses kinetic properties suggesting that it plays an important regulatory role in dehydroepiandrosterone sulfate secretion. In order to study the localization of the enzyme in the respective zones and cells of the cortex, an antibody to the pure enzyme was raised and the immunoglobulin G fraction employed in the peroxidase-antiperoxidase method. Staining was confined to the zona reticularis but was unevenly distributed throughout the cells. Electron microscopic examination of sections prepared from fresh adrenal tissue fixed in glutaraldehyde, revealed that the enzyme was predominantly clustered around lipid droplets. It is suggested that this may reflect an association of organelles, cholesterol being transported from lipid droplets to surrounding mitochondria, and pregnenolone then being converted to dehydroepiandrosterone in the adjacent endoplasmic reticulum and thence immediately sulfurylated.

Conversion of 7alpha3H-testosterone to 17beta-oestradiol by human mammary carcinoma tissue in vitro has been demonstrated. It was characterized unequivocally by conversion to 17beta-oestradiol-3-sulphate upon incubation with adenosine-3'-phosphate-5'-phosphosulphate and the highly specific enzyme oestrogen sulphotransferase.

The metabolism of 17 beta-estradiol in both estrogen receptor positive and negative human breast cancer cell lines has been compared. Initial experiments in which confluent cells were exposed to 1 nM [3H]17 beta-estradiol for 24 h, revealed that the main metabolites formed by estrogen receptor positive MCF-7 and ZR-75-1 cells were 17 beta-estradiol-3-sulfate (together with lesser amounts of estrone sulfate) and estrone. In estrogen receptor negative cell lines, production of estrogen sulfates was either significantly lower (MDA-MB-231 cells) than receptor positive cells, or failed to be produced at all (MDA-MB-330 cells). In both these receptor negative cell lines, production of estrone was significantly higher than in receptor positive cells. Accumulation of estrogen sulfates resulted from attainment of a steady state between synthesis catalysed by estrogen sulfotransferase and degradation catalysed by estrogen sulfatase. The former was present in the cytosol and showed a very high affinity for 17 beta-estradiol and estrone (low nM range). Complex initial velocity versus estrogen substrate curves were obtained with enzyme purified 106-fold by affinity chromatography. Such curves were consistent with a rate equation of degree 3 or 4 and suggest the presence of cooperatively linked dependent binding sites.

The high concentrations of dehydroepiandrosterone and its 3beta-sulfate in the blood are potential preocursors for further metabolism by normal and tumorous human mammary tissue. In vitro metabolism of 7n-3H- and 1,2,6,7(n)-3H-dehydroepiandrosterone by fifteen mammary tumors was examined. Some 10--50% of the radioactivity recovered was in the form of 7-oxygenated derivatives: the major metabolite being 7alpha-hydroxydehydroepiandrosterone accompanied by lesser amounts of the 7beta-epimer. 5-Androstene-3beta,17beta-diol was formed in all but one case. Evidence showed that the high yield of 7alpha-hydroxy derivative resulted from direct action of a 7alpha-hydroxylase capable of using both dehydroepiandrosterone and 5-androstene-3beta,17beta-diol as substrates. Although 5-androstene-3beta,17beta-diol competed with estradiol-17beta for the estrogen receptor, this property was considerably reduced as a consequence of the introduction of a 7alpha-hydroxyl or 16alpha-hydroxyl group. Dehydroepiandrosterone, which competed less effectively for the estrogen receptor site, showed almost no affinity for the site upon the introduction of a 7alhpa-hydrocyl group. A regulatory role for the 7alpha-hydroxylase is outlined.

Estrogen sulfotransferase (EC 2.8.2.4) activity and estrogen receptor levels were measured in 32 human primary breast cancer cytosol preparations. Two types of tumors were identified: type 1, in which estrogen sulfotransferase levels were low (less than 40 pmol 17 beta-estradiol 3-sulfate formed per mg protein per 2 hr) and were independent of [35S]adenosine 3'-phosphate 5'-phosphosulfate production from [35S]sulfate and adenosine triphosphate, and type 2, in which estrogen sulfotransferase levels ranged from 50 to 200 pmol 17 beta-estradiol 3-sulfate per mg protein per 2 hr and were correlated with [35S]adenosine 3'-phosphate 5'-phosphosulfate formation (r = 0.70; p less than 0.005). In type 1 tumors, 11 of 16 were estrogen receptor negative; in type 2 tumors, 2 of 16 were receptor negative. Estrogen sulfotransferase levels in receptor-negative tumors were significantly lower than the levels in receptor-positive tumors (p = 0.025).

Dehydroepiandrosterone (DHEA) and 5-androstene-3 beta,17 beta-diol (ADIOL) were determined by radioimmunoassay in human primary mammary cancer cytosol preparations. The range and means +/- S.D. (ng/g, wet weight, of tissue) in individual tumors were: DHE, 12.3 +/- 14.4, n = 34; and ADIOL, 2.7 +/- 2.1, n = 43. In 23 tumors in which both steroids were measured in the same extract, they were significantly correlated, and in these tumors the ratio of ADIOL to DHEA was lower in estrogen receptor (ERC)-negative than in ERC-positive tumors, but this difference was not significant. The ratio of ADIOL to DHEA was 5-fold higher in purified nuclei obtained from pooled primary mammary cancer tissue compared to that in the cytosol. DHEA was present in the cytosol of tumors from premenopausal women in significantly higher concentrations than in cytosols of postmenopausal women [0.73 +/- 0.49 ng/mg cytosol protein (n = 14) versus 0.35 +/- 0.35 (n = 19); p < 0.02], whereas the concentrations of ADIOL were similar [0.12 +/- 0.09 ng/mg cytosol protein (n = 18) and 0.10 +/- 0.11 (n = 25), for pre- and postmenopausal women, respectively]. In ERC-positive tumors, there was a negative correlation between ERC concentration and cytosol ADIOL levels in both premenopausal (r = -0.46, n = 10) and postmenopausal (r = -0.24; n = 20) subjects and also DHEA levels in postmenopausal women only (r = -0.30; n = 12). However, none of these correlations reached statistical significance. In view of the known high affinity of ADIOL for ERC (Kd approximately 6 nM) and its estrogen-like activity in vivo, these data suggest that the concentration of ADIOL in the tumor cytosols is sufficiently high to translocate ERC and provoke an estrogen response.

Microcolonial structures have been harvested from desert rock samples for cultivation and ultrastructural examination. The results indicate that these microcolonial structures are fungi previously unrecognized as inhabitants of desert rocks.

The mechanism of activation of soluble guanylate cyclase purified from bovine lung by high molecular weight, nitrosyl-hemoprotein complexes is reported. Heme-containing, heme-deficient, and heme-reconstituted forms of guanylate cyclase were studied. Nitric oxide (NO) and nitroso compounds activated heme-containing and heme-reconstituted enzymes (over 50-fold), with an accompanying shift in the Soret absorption peak from 431 to 398 nm, but failed to activate or alter the spectral characteristics of heme-deficient enzyme. In contrast, preformed NO-hemoprotein complexes as well as low molecular weight NO-heme activated all forms of guanylate cyclase. Heme-deficient guanylate cyclase was first reacted with excess amounts of NO-hemoglobin, NO-myoglobin, or NO-catalase and then rapidly separated from the NO-hemoprotein by column chromatography. Spectrophotometric analysis indicated that the NO-heme moiety was transferred from each of the NO-hemoproteins to heme-deficient guanylate cyclase. Approximately 1 mol of NO-heme was bound per mol of holoenzyme and the specific activity of this enzyme form was over 50-fold greater than that of unreacted, heme-deficient enzyme. NO-heme was tightly bound to guanylate cyclase as no transfer of enzyme-bound NO-heme to apohemoglobin was evident. Enzyme activated by NO-hemoproteins closely resembled, kinetically, that activated by NO or NO-heme. In contrast, reactions between heme-deficient guanylate cyclase and hemoproteins did not result in heme transfer, whereas heme alone rapidly reconstituted the enzyme. These observations indicate that soluble guanylate cyclase can be readily reconstituted with, and thereby activated by, NO-heme through an exchange reaction with NO-hemoproteins.

The properties of fatty acyl coenzyme A: estradiol-17 beta acyl transferase in microsomes derived from pooled human mammary cancer tissue have been examined. A pH optimum of 5.5 was found and addition of long-chained fatty acyl CoAs increased estradiol-17 beta (E2) 17-monoacyl ester synthesis; the apparent Km for E2 being 8 microM when oleoyl CoA, linolenoyl CoA or palmitoyl CoA were employed. Testosterone, dehydroepiandrosterone, and 5-androsterone-3 beta, 17 beta-diol acted as competitive inhibitors with Ki values of 36, 36 and 46 microM, respectively. The composition of E2 fatty acyl esters (E2-L) formed by incubation of [3H]E2 with human mammary cancer tissue and human mammary cancer cell lines has been determined by HPLC. Although the composition of E2-L in estrogen receptor negative cell lines (MDA-MB-231 and MDA-MB-330) was generally similar to that found for MCF-7 cells (estrogen receptor positive) and pooled human mammary cancer tissue, the former cell lines contained a 3-fold higher relative concentration of E2-17 beta stearate. MCF-7 cells were exposed to 30 nM [3H]E2 and the composition of the isolated [3H]E2-L fraction studied at various time intervals. At 0.5 h, the intracellular concentration of E2-L was 1.8 +/- 0.4 (SEM) pmol/mg DNA which increased to values of 3.6 +/- 0.6 and 4.3 +/- 0.5 at 4 h and 16 h, respectively. In the subsequent 3 h following transfer to medium lacking [3H]E2, the concentration of E2-L declined to 3.7 +/- 0.3 pmol/mg DNA. The subfraction of E2-L composed of E2-17 beta arachidonate, linolenate and docosahexaenoate, was seen to decline in relative abundance after 0.5 h and to reach significantly lower relative levels at 16 h, and again in the 3 h period following estrogen withdrawal. The data suggests that these components, derived from essential fatty acids, are more metabolically active. This may then provide a new lead to link these novel estrogen derivatives with the established relationship between unsaturated fatty acids and an increased mammary cancer incidence.

It has been established that progesterone will induce 17 beta-estradiol (E2) dehydrogenase in the human endometrium. Whether it plays a similar role in the induction of estrogen sulfotransferase is not known, although this is likely, since estrone sulfate is the main metabolite of E2 when incubated with secretory, but not proliferative, human endometrium. We have now examined the influence of progesterone on both enzymes in endometrial tissue in organ culture. Estrogen sulfotransferase activity was not detectable in the cytosol of proliferative tissue when cultured in the absence of hormone, but was induced by culture in the presence of progesterone to a value (mean +/- SEM) of 19.7 +/- 5.3 pmol E2-3-sulfate h-1 mg cytosol protein-1. A significant (P less than 0.05) induction of E2 dehydrogenase activity was also observed in the same tissues [from 3.7 +/- 1.9 to 10.4 +/- 2.7 (mean +/- SEM) nmol estrone h-1 mg microsomal protein-1]. Corresponding values for secretory endometrium, when cultured under identical conditions in the absence of progesterone, were 20.3 +/- 11.6 pmole h-1 mg-1 and 31.1 +/- 25.1 nmol h-1 mg-1 for estrogen sulfotransferase and E2 dehydrogenase, respectively. Values not significantly different from these were obtained when progesterone was present in the cultures. These data indicate that progesterone secretion during the luteal phase is responsible for the induction of both E2 dehydrogenase and sulfotransferase activities in the endometrium. It is likely that these enzymes are closely coupled, resulting in the rapid metabolism of E2 by formation and excretion of estrone sulfate.

The spectral reflectivity (0.30 to 1.10 microns) of several asteroids has been measured for the first time. The reflection spectrum for Vesta contains a strong absorption band centered near 0.9 micron and a weaker absorption feature between 0.5 and 0.6 micron. The reflectivity decreases strongly in the ultraviolet. The reflection spectrum for the asteroid Pallas and probably for Ceres does not contain the 0.9-micron band. Vesta shows the strongest and best-defined absorption bands yet seen in the reflection spectrum for the solid surface of an object in the solar system. The strong 0.9-micron band arises from electronic absorptions in ferrous iron on the M2 site of a magnesian pyroxene. Comparison with laboratory measurements on meteorites and Apollo 11 samples indicates that the surface of Vesta has a composition very similar to that of certain basaltic achondrites.

Twelve rock chips and two samples of fines all have electronic absorption bands in diffuse reflected light between 0.32 and 2.5 micrometers. Major bands occur between 0.94 and 1.00 micrometer and at 2.0 micrometers, and arise from Fe(2+) in clinopyroxene and to a lesser extent in olivine. A band at 0.95 micrometer and other details of curve slope and shape for the lunar surface fines match McCord's telescopic curve for an 18-kilometer area that includes the Apollo-il site. Results confirm mineralogical predictions based on telescopic data and support the feasibility of obtaining mineralogical information by remote and in glass content. reflectivity measurements.