The capacity of human chorionic gonadotrophin (hCG) to raise plasma progestagen levels during the first 8 days of gestation in gilts was examined. The effective half-times of hCG in gilts treated with 500 and 5000 i.u. hCG were 29.1 and 26.3 h respectively (P greater than 0.05). Neither 500 nor 5000 i.u. hCG caused rises in peripheral concentrations of progesterone or pregnenolone sulphate, and plasma pregnenolone concentrations declined (P less than 0.05) following hCG treatment. Apart from diminished total corpus luteal weights in gilts treated with 500 i.u. hCG (P less than 0.05) and lower peripheral progesterone levels in gilts treated with 5000 i.u. hCG (P less than 0.05), ovarian and plasma steroid characteristics of hCG-treated animals between 23 and 25 days of gestation were similar to control values. Furthermore, treatment with hCG did not affect embryo survival during the first 4 weeks of pregnancy, and plasma oestrone/oestrone sulphate levels provided no evidence for differences between control and treated animals in trophoblastic outgrowth. These results challenge the rationale for the treatment of early pregnant sows with hCG in order to reduce the levels of embryonic wastage in early pregnancy.

The activity of 17 beta-hydroxysteroid dehydrogenase has been investigated in human subcutaneous adipose tissue. Using oestrone as substrate, oestradiol formation was linear with time and the concentration of protein in the tissue homogenate. The optimum pH was 8.0 and the Km for oestrone was 2.5 x 10(-6) M. With NADH, the production of oestradiol was about 30% of that with NADPH. Oestradiol was also a substrate for the enzyme although under the experimental conditions used reduction of oestrone appeared to be favoured in adipose tissue. In the presence of progesterone (31.8 x 10(-6) M) the Km for oestrone was increased fivefold.

Oestrone sulphatase activity was determined in 12,500 g supernatant of rat homogenates. The conditions used were 0.5 mM oestrone sulphate and 30 min incubation at pH 8.0 and 37 degrees C. The enzyme activity in uteri from normal animals was found to be 5.1 +/- 0.7 nmol (mg protein)-1 h-1. In ovariectomized and hypophysectomized animals the values were significantly higher, whereas subcutaneous administration of 17 beta-oestradiol to such rats resulted in significantly decreased oestrone sulphatase activities. Progesterone increased the enzyme activity of intact rats. It is concluded that the uterine tissue of rats contains oestrone sulphatase which may be of biological importance and which is inhibited by oestrogen.

Blood samples from 4 mares during the late luteal phase, oestrus, early pregnancy and up to about 150 days of gestation were analysed for 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), progesterone, PMSG and oestrone sulphate by radioimmunoassays. During the late luteal phase, at the time of corpus luteum regression and decreasing progesterone levels, PGFM peaks were recorded. During early pregnancy (i.e. from mating and up to about Day 30) no such peaks were detected. After mating the progesterone levels increased and remained high throughout the observation period. During the oestrous cycle PMSG levels tended to reflect gonadotrophic activity because of high cross-reaction with horse LH and horse FSH. During early pregnancy PMSG levels increased at around Day 40, reaching maximum values between Days 50 and 80, when the blood concentration was 1000 times higher than values during oestrus. Oestrone sulphate concentrations increased about 3-fold during oestrus and about 10-fold at the peak of PMSG. After about Days 70-75 of pregnancy the levels of oestrone sulphate increased further and values of greater than 250 nmol/l were reached around Day 100.

Concentrations of progesterone and oestrogens were determined by radioimmunoassay in the peripheral blood of 22 Percheron and Breton breed mares from the 6th day of oestrus to the 150th day of pregnancy. Periodical variation patterns for the mean values of oestrone, oestradiol 17beta and total oestrogens in the cycling mares were found, with two peaks on the third day before and the 15th day after ovulation, and one depression on the 6th day of oestrus. In pregnant mares, the concentrations of oestrone and oestradiol 17beta increased rapidly (P less than 0.05) after Day 105 of gestation. Progesterone levels declined after Day 18 of the cycle in cycling mares, whereas they increased in the pregnant mares. Marked changes in the ratio of total oestrogen to progesterone concentrations were found in cycling mares, especially at oestrus, but in pregnant mares the ratio always remained below 1.00.

We studied the metabolism of testosterone in primary cultures of prostate epithelial cells and fibroblasts obtained from patients with benign prostatic hyperplasia (BPH). The conversion of 3H-testosterone in both cell cultures was predominantly to the oxidative pathway, with the formation of 3H-androstenedione increasing with cell number and time of incubation. Although we also detected some 5 alpha-reductase activity in these cells, the activity in the stroma component (0.00688 pmol/mg protein/min) was nonetheless insignificant when compared to the 5 alpha-reductase activity in the tissue of origin (0.0616 pmol/mg protein/min) and well below the 17 beta-hydroxysteroid dehydrogenase activity of the same cells (0.0518 pmol/mg protein/min). The aromatase activity in our cells was also measured by two separate techniques, but neither the deuterium procedure nor the production of oestrone from androgen precursors yielded any positive results, suggesting that under these experimental conditions there was no aromatase activity within the cells. The shift from the reductive to the oxidative pathways in these primary cell cultures was reminiscent of the androgen-metabolizing enzyme profiles seen in poorly differentiated prostate cancer. Whether this transition is an obligatory step in the development of hormone refractiveness remains to be elucidated.

The aim was to define precisely the FSH secretion pattern in mares during the two ovulatory cycles before, and for 24 days after, the last ovulation of the season and to compare this with the profiles of other reproductive hormones and follicular growth to identify changes which may lead to the termination of follicular cycles. Jugular blood was collected every 6 h from ten light horse mares for 6 weeks in autumn. Samples were assayed for FSH, LH, prolactin, inhibin, oestrone conjugates and progesterone. Luteolysis occurred earlier and periovulatory oestrone, but not inhibin, concentrations were significantly lower in the last than in the second to last cycles. In ovulatory and anovulatory cycles, daily mean FSH concentrations were low at the expected time of ovulation and high between days 9 and 11 (day 0 = ovulation), which were usually after luteolysis. However, the periovulatory FSH nadir was prolonged in the last compared with the second to last cycles, and the difference between peak and trough values was not significant in anovulatory cycles. Between day 5 and day 8, the FSH interpulse interval was approximately 2 days, and did not vary in successive cycles. The LH profile also showed progressive changes as mares entered acyclicity; the surge terminated sooner in the last than in the second to last cycles, and failed to occur when expected in acyclicity. Sporadic prolactin pulses occurred at luteolysis in a similar proportion of ovulatory and anovulatory cycles. These results indicate that inadequate gonadotrophin stimulation in early dioestrus may be a critical event leading to suboptimal follicular and luteal development, and eventually acyclicity. Moreover, the time relationships amongst changes in pituitary and ovarian hormones and follicular growth become increasingly disrupted during the autumn transition, which may contribute to the cessation of cyclicity.

Six Meishan and five Large White hybrid gilts were naturally mated to boars of the same breed during their tenth or third oestrous cycle respectively. Maternal serum progesterone and total oestrone were monitored throughout the pregnancy period. On Day 30 of gestation, all gilts were slaughtered and ovulation rate, embryonic survival, conceptus development and intrauterine steroidogenesis were evaluated. The results of the study confirm previous reports that Meishan pigs have a higher number of live conceptuses (P < 0.03), a higher rate of embryonic survival (92.1% v. 78.6% for Large White hybrids) and a higher ovulation rate (P < 0.02) than Large White hybrid gilts. Embryos from Large White hybrid gilts were heavier (P < 0.001) than Meishan embryos and placental lengths (P < 0.001) and weights (P < 0.001) were greater. The volume of allantoic fluid per conceptus was greater (P < 0.03) in Large White hybrid gilts. The oestradiol concentration in the allantoic fluid was greater in Large White hybrid gilts (P < 0.002), but the progesterone concentration in allantoic fluid did not differ (P>> 0.15) between the breeds. More oestradiol was synthesized in vitro on a wet weight basis from placental tissue in Large White hybrid gilts than in Meishan gilts (P < 0.001); however, a positive linear relationship existed in both breeds between oestradiol synthesis and placental length (P < 0.005). Progesterone concentrations in maternal serum tended to be higher overall (P < 0.1) in Meishan gilts than in Large White hybrid gilts throughout the 30-day period of study and were significantly higher (P < 0.02) from Day 13 to Day 30.(ABSTRACT TRUNCATED AT 250 WORDS)

Total sulphoconjugated and unconjugated dehydroepiandrosterone (DHA) and total oestrone were measured in plasma of intact sheep fetuses, fetuses hypophysectomized at 104-112 days and fetuses bilaterally adrenalectomized at 98-101 days. At 120-127 days, the mean concentrations of total DHA and oestrone in intact fetuses (n = 13) were 29.7 +/- 4.2 (S.E.M.) nmol/l and 14.3 +/- 2.8 nmol/l respectively. At term, the values for total DHA and oestrone in hypophysectomized fetuses (n = 13) of 18.0 +/- 1.9 nmol/l and 9.1 +/- 2.0 nmol/l were significantly (P less than 0.05) lower than the intact group whereas in the adrenalectomized fetuses (n = 8) total DHA (80.8 +/- 13.0 nmol/l) was higher (P less than 0.05) and total oestrone values were similar to the intact animals. Intrafetal infusion of cortisol at term (1 mg/h for 84 h) raised levels of total oestrone in intact (n = 6; 12.3 +/- 2.9 vs 31.6 +/- 8.5 nmol/l) and adrenalectomized (n = 4; 14.2 +/- 2.6 vs 190.6 +/- 53.0 nmol/l) fetuses and of total DHA in hypophysectomized fetuses (n = 7; 16.0 +/- 1.9 vs 31.6 +/- 8.5 nmol/l) while infusion of ACTH (1-24) (5 micrograms/h) was without significant effect in any group. It is concluded that the ovine fetal adrenal in late pregnancy makes no significant contribution either to the high circulating concentrations of DHA sulphate or to the substrates for placental oestrogen synthesis.

From the Antarctic sponge Lyssodendoryx flabellata, a new polycyclic compound, which we named flabellone, related to the oestrogenic hormone oestrone, has been elucidated by spectrometric and spectroscopic means. Along with flabellone, a glycosphingolipid (GSL) mixture featuring an unusual α-fucofuranosyl-3-β-glucopyranoside unit structurally identical to the previously reported terpioside has been isolated and identified. The mixture of GSL homologues exhibited inhibitory effects in mixed lymphocyte reactions on human cells.

To investigate the causes and mechanisms of foetal loss in Norwegian dairy goats, blood parameters in 40 goats that lost foetuses were compared with those in 40 goats that experienced a normal pregnancy. High mean levels of 15-ketodihydro-PGF2alpha, and low mean levels of oestrone sulphate throughout pregnancy were associated with foetal loss. The mean oestrone sulphate level was low before abortion, and the distinct peak that occurred at parturition in the control goats was not observed in connection with abortion. Association of other blood parameters with foetal loss was not detected. Infectious agents and toxins did not appear to be major causes of foetal loss in this study. The normal level of progesterone and cortisol in goats with foetal loss indicated that the function of the corpus luteum and adrenal glands, respectively, were not disturbed. The rapid decline in progesterone level associated with foetal loss may therefore be a result, rather than the cause, of foetal death. The lowered level of oestrone sulphate and elevated level of 15-ketodihydro-PGF2alpha in goats with foetal loss clearly indicated that the endocrine foetal-placental function was disturbed.

We studied a group of 398 patients who had been receiving estrogen replacement therapy since 1976. Group I consisted of 138 patients who received Premarin (conjugated equine estrogen, Ayerst) in two different dosages (0.625; 1.25 mg) and progestational agents such as Neogest (Norgestrel, Schering), Duphaston (Dydrogesterone, Duphar) 5 mg and Primolut N (Norethisterone, Schering) 5 mg, for a period ranging between 7 and 21 days. Group II consisted of 106 patients who received Harmogen (Piperazine Oestrone Sulphate, Abbott) in two different dosages (1.5 mg; 2.25 mg) with the above-mentioned progestational agents for a period ranging between 7 and 21 days. Group III consisted of 154 patients who received Progynova (Oestradiol Valerate, Schering) in two different dosages (1 mg; 2 mg) with the above-mentioned progestational agents for a period ranging between 7 and 21 days. When increasing dosages of estrogen with progestational agents were added for 7 days, this produced cystic hyperplasia of the endometrium. When the duration of progestational agents was increased to 10 days or more, a more atrophic and secretory endometrium resulted and there was no incidence of cystic hyperplasia.

Dehydroepiandrosterone sulfate (DHA-S) plays a critical role in cervical dilatation at labor. Incubation of cervical fibroblasts with [3H]DHA-S caused a rapid and saturable increase in cellular radioactivity: an apparent equilibrium was reached by 2 min. There was no detectable conversion of DHA-S into DHA or oestradiol. When the fibroblasts loaded with [3H]DHA-S were homogenized and fractionated, the specific radioactivity in the plasma membrane fraction was enriched approximately 8- to 9-fold compared with the whole homogenate; only low amounts of radioactivity were observed in the other subcellular fractions. The binding of DHA-S to plasma membrane preparations showed saturation kinetics with an apparent equilibrium dissociation constant (Kd) of 12 nM, and the binding capacity (Bmax) was calculated to be 1.25 fmol/mg protein. Neither DHA nor oestrone sulfate affected [3H]DHA-S binding to the plasma membrane. The plasma membranes of skin fibroblasts did not show specific binding sites for DHA-S. These findings demonstrate the presence of specific binding sites for DHA-S in the plasma membrane of cervical stroma cells. The fetal adrenal steroid may exert its action on cervical ripening at least in part through membrane-associated binding sites, or receptors.

Blood flow transducers were placed around one uterine artery per ewe and observations of the rate of blood flow through this artery and the peripheral plasma concentrations of free, unconjugated oestrone, oestradiol and progestagens were made at intervals of 1-3 days during the last 2-3 weeks of pregnancy and at hourly intervals after spontaneous delivery at term. Rates of uterine blood flow decreased on average by 50% or more within the first hours of parturition and patterns of change in blood flow varied considerably among the animals. Spontaneous daily (pre partum) and hourly (post partum) changes in uterine blood flow were significantly correlated (P < 0.01) with the product of the concentrations of progestagens and of total free oestrogens (oestrone and oestradiol) and with the product of progestagens and oestradiol in peripheral blood.

Rat alpha-foetoprotein (AFP) was shown to inhibit the formation of water soluble metabolities of oestrone and oestradiol by incubation with microsomes from rat liver in the presence of NADPH. The results support the proposal that in young animals the low activity of enzymes responsible of oestradiol metabolism may be due in part to the presence of AFP and not only to the low level of these enzymes.

An enzyme that catalyzes the transfer of sulphate from 3'-phosphoadenosine 5'-phosphosulphate to bile salts was purified from human liver cytosol by chromatography on DEAE-Sephadex and Sephadex G-200, by agarose suspension electrophoresis and by isoelectric focusing in free solution. The purified enzyme was also active towards oestrone, dehydroepiandrosterone and phenol. No other liver steroid sulphotransferases could be detected during this purification procedure. Km values of 1.8 . 10(-6) M and 3.3 . 10(-6) M for glycolithocholate and 3'-phosphoadenosine 5'-phosphosulphate respectively were found. The sulphotransferase has an isoelectric point of 5.5. The enzyme was markedly activated by Mg2+, Mn2+ and Co2+ and inhibited by Cu2+, Fe2+ and Zn2+. Chenodeoxycholate and deoxycholate were sulphated at the 7-OH and 12-OH position, respectively. No bile salt disulphate formation was detected. A 30-fold increase in specific activity was obtained, although the purification based on ultraviolet light measurements was considerably higher.

Human placental tissues have been shown to contain gonadotrophin-releasing hormone-(GnRH)-like activity. Thus, the effect of a potent GnRH antagonist (N-Ac-Pro1,D-p-Cl-Phe2,D-Nal(2)3,6-GnRH, obtained from Syntex Laboratories) on placental hormonal release was studied. Explant cultures of placentae of 6 to 15 weeks' gestation were studied. This GnRH antagonist did not inhibit the alpha human chorionic gonadotrophin (alpha hCG), human chorionic gonadotrophin (hCG), oestrone or oestradiol release from the six- and nine-week placental cultures, but greatly suppressed the release of these hormones in the placental cultures from 13- and 15-week gestations. Synthetic GnRH partially reversed the action of this antagonist on the hormonal releases in the 15-week placental cultures. These data demonstrate a gestational age-related action of this antagonist on placental hormonal release. Thus, a role for the endogenous GnRH-like activity of the placenta in the control of placental hormonogenesis is indicated.

Steroid sulphatase, which can hydrolyse 3-hydroxysteroid sulphates, has important roles in several physiological and pathological processes. A number of steroid sulphatase inhibitors have now been developed, of which the most potent to date is oestrone-3-O-sulphamate (EMATE). This inhibitor inactivates steroid sulphatase in an irreversible, time- and concentration-dependent manner. In order to be able to use a radiolabelled derivative of EMATE to study the active site, it will be essential to prepare the steroid sulphatase in a pure form. For this, attempts have been made to express the protein, using the steroid sulphatase cDNA, in the pGEX2T expression system and also to express a mutant form of the protein, in which the putative membrane-spanning domain was deleted, in CHO cells. In addition, a soluble steroid sulphatase has been identified from the snail Helix pomatia. This steroid sulphatase is inhibited by EMATE in an irreversible manner, similar to the human steroid sulphatase and appears to possess a histidine residue at its active site. The expression and/or isolation of a steroid sulphatase, in conjunction with the use of a radiolabelled derivative of EMATE should allow important new information about the active site of this enzyme and the mechanism of its inactivation to be obtained.

The aim of this study was to use measurements of urinary steroid glucuronides to confirm the suppression of ovulation of ovulation in women taking oral contraceptives. Urinary concentrations of oestrone-3-glucuronide (E1G) and pregnanediol-3 alpha-glucuronide (Pd-3-G) were measured by radioimmunoassay in early morning urine samples from six normally-menstruating women and six women who were taking combined oral contraceptives. In the normally-menstruating women, E1G concentrations, and the E1G/Pd-3-G ratio, increased 2-3 fold before ovulation. There was no midcycle increase in either measure in women taking oral contraceptives. We suggest that measurement of these steroid metabolites provides a means of assessing the anti-ovulatory effects of oral contraceptives.

Six normal stallions of light horse breeds aged 5-17 years were used from fall to winter to investigate the difference between steroid hormone concentrations in testicular and jugular venous blood before and after exogenous GnRH. At 48 h before experimentation, an indwelling cannula was placed surgically in the testicular vein of the stallion. After the stallion recovered from anaesthesia, a catheter was placed percutaneously in the jugular vein. Each stallion was housed in a tie stall to allow simultaneous sampling of jugular or testicular blood. On the first and second sampling days, respectively, 1 ml of physiological saline solution and a 1 ml solution of GnRH (25 micrograms) were administered intravenously. Samples were taken from both sites at intervals from 60 min before treatment to 780 min after treatment. Plasma was analyzed for luteinising hormone (LH) and follicle-stimulating hormone (FSH), 17 beta-hydroxyandrogens (androgens), oestrone and oestrogen conjugates by radioimmunoassay. Pre-treatment (baseline) plasma concentrations of both LH and FSH between jugular and testicular samples were similar. The difference between basal levels of jugular and testicular androgens, oestrone and oestrogen conjugates were 144-fold, 60-fold and 13-fold respectively, although individual variation was observed. A low dose of exogenous GnRH produced a significant LH and FSH response in testicular and jugular plasma (P less than 0.05). There were no significant changes in steroid secretion caused by the increases in LH and FSH (P greater than 0.05), although individual variation in the androgen response was apparent (P less than 0.1). There was a positive correlation between basal testicular venous androgen levels and the magnitude of the FSH response to GnRH (P less than 0.05). Significant correlations between baseline oestrogens and the magnitude of the gonadotrophin response was not observed. Surgery depressed jugular oestrogen conjugate values (P less than 0.001) when compared to pre-surgical samples. Spermatogenesis also was depressed (P less than 0.01) by surgical manipulation, although total viable spermatozoa counts returned to normal limits within 3-5 months post operatively. We developed a model that allows the study of dynamic endocrine events associated with the hypophyseal-gonadal axis of the stallion. Our findings confirm the presence of a testicular-jugular hormone gradient in the unanaesthetized stallion. We have demonstrated that a relatively low dose of GnRH can induce a significant gonadotrophin response and a variable androgen response, but not a significant oestrogen response. Although baseline levels of androgens and not oestrone and oestrogen conjugates appeared to affect pituitary responsiveness, other steroidogenic components may be involved.(ABSTRACT TRUNCATED AT 400 WORDS)

4C-Labelled mestranol, 3-O-methyl oestrone and cholesterol-5 alpha,6 alpha-oxide have been prepared. Along with the natural oestrogens, E1 and E2, and other steroids, these compounds have been used to determine the extent of their physical association with DNA. Analysis of binding both by equilibrium solubilization and by caesium chloride density gradient centrifugation showed the same relative order of binding: mestranol greater than 3-O-methyl oestrone greater than oestrone greater than cholic acid greater than cholesterol-5 alpha,6 alpha-oxide greater than progesterone, testosterone greater than oestradiol. DNA from Micrococcus lysodeikticus showed a higher affinity for cholic acid than did calf thymus DNA, while pretreatment of the latter with proteinase K somewhat reduced the level of physical binding of oestrone.