Simultaneous Measurement of Plasma Progesterone, 17-Hydroxyprogesterone and Estradiol-17B by Radioimmunoassay

Impaired steroidogenesis in the luteal phase of the reproductive cycle and during pregnancy in rhesus monkeys immunized with the beta-subunit of ovine luteinizing hormone

Monkeys immunized with the beta-subunit of ovine luteinizing hormone (oLH beta) develop antibodies which cross react with rhesus chorionic gonadotropin (rhCG) and luteinizing hormone (rhLH). Immunization causes shortened menstrual cycles and reduced fertility. Fertility can be restored by administration of medroxyprogesterone acetate (MPA) during the first 5 weeks of pregnancy. In the present study, we have measured the effects of circulating oLH beta-antibodies on peripheral estradiol, progesterone and 17 alpha OH-progesterone (17OH-P) concentrations throughout the menstrual cycle and during gestation in monkeys which became pregnant following MPA-treatment. Progesterone concentrations were markedly reduced during the luteal phase in cycling animals and the luteal phase of the cycle was significantly shorter as compared to non-immunized controls. Concentrations of estradiol and 17OH-P in the peripheral circulation were not affected by the oLH beta-antibodies. In immunized monkeys which became pregnant following MPA-treatment, progesterone and 17OH-P levels were consistently lower and estradiol concentrations were increased during the second and third trimesters. Our results show that circulating antibodies to oLH beta have multiple endocrinological effects. Corpus luteum function is impaired in cycling monkeys and during the early part of pregnancy. In addition, the pattern of steroid secretion remains abnormal in pregnant monkeys even after the luteal-placental shift.

Endocrine evaluation in infertile men with varicocele

Steroidal and gonadotropic secretion were studied in infertile men with varicocele. Hormonal values were compared with those from control groups. No significant difference was found between control and pathologic groups in relation to prolactin secretion. FSH and LH showed increased basal values in 16% and 8% these cases in the group studies. Exaggerated gonadotropic response to LH-RH was observed in 33.3% of the patients. Basal testosterone and estradiol levels were found to be reduced in 18% and 30% of the cases, respectively. Testosterone response to LH-RH was also depressed in men with varicocele. Significant correlations were still observed between FSH and LH, LH and testosterone and testosterone and estradiol in infertile men with varicocele. These findings suggest both a tubular and interstitial involvement in varicocele and support the hypothesis of a Leydig cell deficiency in this pathology.

Effect of testosterone enanthate on testis size

We treated chronically 39 normal men with a depot androgen, testosterone enanthate (200 mg. intramuscularly), to assess its potential as a male contraceptive agent. Careful examination and quantification of testicular volume were done before, during and after several dose regimens of androgen therapy. After 4 months of weekly or bimonthly treatment with testosterone enanthate testicular volume decreased by 19.0 plus or minus 2.1 and 16.5 plus or minus 3.4 per cent, respectively. Decrease in testicular volume was related directly to decrease in sperm count. A total of 17 subjects on either weekly or bimonthly injections failed to suppress sperm counts to less than 5 million per cc after 16 weeks; testicular volume was not significantly less than control at this time. Four to 12 weeks of additional weekly injections decreased sperm counts to less than 5 million per cc in 13 of the 17 patients and decreased testicular volume by 23.0 plus or minus 4.8 per cent. The 16 additional weeks of less frequent injections (every 3 or 4 weeks) resulted in an increase in testicular volume with a return to normal size after treatment was discontinued.

Endocrine effects of acute and chronic cimetidine administration

In normal men, acute oral administration of 300 mg cimetidine or intravenous injection of 50 mg of the drug had no effect on prolactin release. In contrast, intravenous injection of 150 or 300 mg led to substantial increments in serum prolactin. Peptic ulcer patients were randomly assigned to treatment with either cimetidine or antacid. Serial blood sampling until ulcer healing showed no significant changes in serum prolactin, testosterone, free testosterone, estradiol, LH, or FSH in either group. It is likely that the impotence and breast changes occasionally seen during cimetidine therapy are due to peripheral antagonism of androgen action rather than to alterations in circulating hormone levels.

The effect of a synthetic progestogen, ethylnorgestrienone, on hypothalamic-pituitary-ovarian function, cervical mucus, vaginal cytology, and endometrial morphology

The antifertility mechanism of a new progestin preparation, ethylnorgestrienone (13 beta-ethyl-17 alpha-ethynyl-17-hydroxy-gona-4,9,11-triene-3-one) (R2323), was evaluated. The compound was administered orally in doses of 5 mg weekly to seven subjects for a total of nine treatment cycles. Each woman served as her own control and was studied during a normal menstrual cycle followed by a cycle in which she received R2323. Serum concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), estradiol, and progesterone, as well as cervical mucus properties, were studied serially during the control and treatment cycles. Results indicated that all control cycles were ovulatory. Ovulatory gonadotropin patterns were observed in four treated cycles, but preovulatory FSH and LH peaks and progesterone production during the luteal phase were suppressed significantly. Estradiol levels showed an early increase during the follicular phase and a significantly decreased preovulatory peak. Cervical mucus properties were altered and sperm penetration in cervical mucus was inhibited in all treatment cycles. These findings suggest that at least two different factors might be involved in the contraceptive mechanism of R2323: (1) alteration of the ovulatory process and progesterone production, and (2) cervical mucus changes leading to inhibition of sperm migration.

Testicular function in Klinefelter's syndrome

Testicular venous effluent was obtained by selective catheterization from 2 subjects with chromatin-positive Klinefelter's syndrome. In both of these subjects the testosterone concentration was reduced, whereas the estradiol concentration was normal or slightly increased in 1 and reduced to a much lesser extent than the testosterone level in the other. The testosterone/estradiol ratios in both subjects were in the range of 180, whereas in the normal subjects the mean testosterone/estradiol ratio in the spermatic venous effluent was 582.

Steroidogenesis by the human oocyte-cumulus cell complex in vitro

The ability of the human oocyte-cumulus cell complex to synthesize progesterone, androgens and estrogens and to modify its endocrine environment in vitro was investigated. Germinal-vesicle stage oocytes with adhering layers of cumulus cells were recovered from human ovaries and maintained for 40--50 h in vitro in a culture medium with or without antral fluid. The results show that oocyte-cumulus (O-C) cell complexes were capable of synthesizing progesterone, androgens and estrogens. Oocytes with the capacity of resuming meiosis in vitro were part of an O-C complex producing significantly more progesterone than those O-C complexes containing oocytes incapable of resuming meiosis. Irrespective of the stage of oocyte maturation at the end of culture, testosterone and estrone were respectively the major androgen and estrogen produced. It is concluded that the oocyte-cumulus compartment of the antral follicle is a steroidogenically competent unit and that it has the capacity to modify the endocrine microenvironment of the follicle.

Nursing frequency, gonadal function, and birth spacing among !Kung hunter-gatherers

Mothers among !Kung hunter-gatherers nurse briefly and frequently, with brief intervals between nursing bouts (mean +/- standard error, 13.19 +/- 1.28 minutes). The low levels of 17 beta-estradiol and progesterone in the serum of the mother are correlated with infant's age and with interbout interval, but not with total nursing time. Maternal gonadal function is apparently suppressed by a timing-dependent, prolactin-mediated effect of breast stimulation. Interbout interval may be a key variable in lactation infertility. If so, it solves the puzzle of !Kung birth spacing.

Mode of action of DL-norgestrel and ethinylestradiol combination in postcoital contraception

Possible mechanisms of action of a combination of ethinylestradiol (EE) and dl-norgestrel as a postcoital contraceptive agent were studied in 12 healthy female volunteers. An oral dose of 0.1 mg of EE and 1.0 mg of dl-norgestrel was given at the predicted time of ovulation and again 12 hours later. Serum luteinizing hormone, prolactin, progesterone, 17 alpha-hydroxyprogesterone, and estradiol were measured by specific radioimmunoassays in blood samples obtained daily from the 8th day of the menstrual cycle to the 1st day of menses. Hormone profiles suggested that the medication elicited a range of individual variations in pituitary and/or ovarian responses. Histologic examination of the endometrium consistently showed significant alteration in endometrial development with a dissociation in maturation of glandular and stomal components. This postcoital contraceptive acts either by (1) suppressing ovulation or (2) disrupting luteal function by acting directly on the corpus luteum or by interfering with appropriate endometrial responses to ovarian steroids.

Serum luteinizing hormone, progesterone, and estradiol levels in relation to broodiness in the turkey (Meleagris gallapavo)

Changes in nesting frequency, serum LH, progesterone, and estradiol were measured in relation to the onset of broodiness in turkeys. In each of two experiments the frequency of nest visits increased about four-fold in the 5 to 7 day interval before oviposition of the last egg associated with the onset of broodiness. In the 9 day period prior to oviposition of this egg LH levels declined from about 12 ng/ml to 6 to 7 ng/ml (Experiment 1) and from about 9 ng/ml to less than 5 ng/ml (Experiment 2). Progesterone levels declined during this same period going from about 2 to 2.5 ng/ml down to less than .5 ng/ml. In the 5 day period following the nadir in serum LH, which occurred on or a day or two after the last egg, levels of this hormone again rose substantially. Estradiol levels, assayed in Experiment 2, were generally low with many samples below detectability (less than 3 pg/ml). There were no consistent changes in serum estradiol until the day before oviposition of the last egg. On this day, and on the subsequent four days, mean estradiol levels were at a nadir (6 to 9 pg/ml) and rose to levels averaging over 11 pg/ml in the following five day period.

Effects of exercise on the serum concentrations of FSH, LH, progesterone, and estradiol

The effects of 30 min of exercise (74.1 +/- 3.0% (VO2), on the responses of progesterone (P), estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were investigated in 10 women. With such exercise significant increments occurred in P (37.6 +/- 9.5%) and E2 (13.5 +/- 7.5%) (P less than 0.05), whereas no changes were observed in FSH and LH (p greater than 0.05). Exercise in the luteal phase and during menses provoked similar changes in P, but E2 concentrations remained unchanged when exercise occurred during menses (p greater than 0.05). With 8-11 weeks of training the menstrual cycles were quite irregular and retesting of subjects in the same phase of the cycle was not possible. Yet, when subjects were retested after training, no changes occurred in P, E2 or LH (p greater than 0.05) but a decrement did occur in FSH (p less than 0.10). Thus, heavy exercise in untrained subjects provokes significant increments in ovarian hormones, whereas no such increments are observed in trained subjects exercising at the same absolute workload.

Paradoxical effects of D-Trp6-luteinizing hormone-releasing hormone on the hypothalamic-pituitary-gonadal axis in immature female rats

The effect of administration of a superactive and long-acting analog of luteinizing hormone-releasing hormone (LH-RH), D-Trp6-LH-RH, in doses of 0.05 or 1 microgram/day for 10 days on the hypothalamic-pituitary-gonadal axis was studied in immature female rats. Treatment with a 0.05-microgram dose of analog produced few changes as compared with the control group. Treatment with 1 microgram of D-Trp6-LH-RH did not affect the body weight or the pituitary weight, but increased ovarian weight and decreased uterine weight; elevated serum gonadotropin levels; and lowered the pituitary LH content. This depletion of pituitary LH content was associated with a low pituitary responsiveness to LH-RH. Serum estradiol levels were not modified, suggesting that decreased uterine weight reflects a direct and extrapituitary effect of this analog. The hypothalamic LH-RH content was higher, indicating a possible inhibition of the release of endogenous LH-RH. A delay in vaginal opening was also observed. This indicates that large doses of D-Trp6-LH-RH may interfere with the process of puberty in rats. These findings extend other reports about the paradoxical antifertility effects of large doses of stimulatory analogs of LH-RH.

Effect of estrogen on rate of 59Fe uptake by hemopoietic tissue in Japanese quail

Injection of 2 mg estradiol valerate into male Japanese quail caused the rate of 59Fe uptake by the skeleton to drop 70% within 48 h. This phenomenon was due to an increase in the iron-binding capacity of the plasma induced by estrogen that caused a substantial decline in the availability of the label for hematopoiesis and to partial inhibition of hematopoiesis by estrogen directly. The changes in 59Fe uptake induced by estrogen were accompanied by a significant drop in circulating red blood cell concentration and a substantial rise in plasma volume. These altered physiological conditions were similar to those normally found in the laying hen.

17-Hydroxyprogesterone in normal children and congenital adrenal hyperplasia. Measurement in serum by radioimmunoassay after thin-layer chromatography

Serum 17alpha-hydroxyprogesterone (17 OH-P) was measured by a specific radioimmunoassay technique combined with thin-layer chromatography. Normal values for children are less than 1.1 microgram/1 (less than 3.3 nmol/l)--corresponding to values found in the literature. In congenital adrenal hyperplasia (CAH) values up to several hundred microgram/l are found. The values rise after ACTH stimulation and are suppressed by decadrone or cortisone treatment. The rise in 17 ketosteroids and pregnanetriol in untreated CAH is relatively smaller (15--25 fold). This clinical sensitivity of 17 OH-P is thus valuable for the diagnosis of CAH (21 hydroxylase deficiency). Furthermore it is easier to take a blood sample than to collect urine for 24 hours. The usefulness in therapeutic monitoring is being studied.

Radioimmunoassay of ovine and bovine serum progesterone without extraction and chromatography

A procedure for the radioimmunoassay of ovine and bovine serum progesterone is described which does not require extraction and chromatography. Serum samples are assayed directly, and a highly specific antiserum that was prepared in rabbits against 11 alpha-hydroxyprogesterone conjugated to bovine serum albumin is used. Interference from serum binding proteins is alleviated by use of a phosphate buffer containing 5% BSA and separation of bound and free tritiated progesterone by a double antibody procedure. Serum samples are assayed in a mini-vial, the bound fraction (double antibody precipitate) is mixed with scintillation solution and the radioactivity is counted in the same vial. The assay procedure is sensitive (10 pg, 100 pg/ml) and has acceptable accuracy and precision. Because there is no extraction or chromatography, serum progesterone is not lost. Most important, the procedure is specific for progesterone and measures serum progesterone concentrations in the ewe and cow which are comparable with those obtained with conventional assay techniques. The progesterone assay described herein provides a rapid, economical procedure that can facilitate the study of ovarian cyclicity and aid in the early diagnosis of pregnancy.

Relationship between steroidogenesis and oocyte maturation in rat graafian follicles cultured in vitro

Rat Graafian follicles were dissected from ovaries during the morning of proestrus and incubated in various media. After an 8 h incubation period, ovarian follicles were collected and analyzed, by radioimmunoassay, for progesterone, 17 alpha-hydroxyprogesterone, androstenedione, estradiol-17 beta, and dihydrotestosterone. Following incubation in proestrus (a.m.) serum, preovulatory follicles secreted all these steroids and the output of progesterone, 17 alpha-hydroxyprogesterone and androstenedione was markedly stimulated following the addition of LH to the media. Follicle-enclosed oocytes resumed meiosis when incubated in proestrus serum without added LH. However, germinal vesicle break-down (GVBD) under these conditions was considerably slower than that observed following addition of LH to the medium. "Spontaneous" maturation of oocytes in proestrus serum was associated with increased production of steroids. Oocyte maturation and steroidogenesis both occurred following incubation of ovarian follicles in serum obtained from hypophysectomized rats. Addition of LH to the media markedly accelerated these responses. These results suggest that oocyte maturation and steroidogenesis also occur in cultured ovarian follicles in the absence of gonadotrophic hormones. The relationship between steroidogenesis and/or spontaneous oocyte maturation are discussed.

Angiotensin stimulates cortisol biosynthesis in human adrenal cells in vitro

Adrenal glands obtained from patients undergoing therapeutic adrenalectomy were used to study the effects of angiotensin on human adrenal steroidogenesis. It was observed that angiotensin stimulated cortisol biosynthesis. Although this has been demonstrated to occur in canine and bovine adrenals, angiotens in-induced cortisol biosynthesis has not been established in man. The possibility that angiotensin merely stimulated glomerulosa cells to secrete precursor steroids which accumulated in the medium and then diffused into fasciculata cells to provide substrate for cortisol biosynthesis was excluded by demonstrating that 3beta-hydroxy-5-pregnen-20-one (pregnenolone) and progesterone (the only pertinent precursors) did not accumulate in angiotensin-stimulated cell suspension. In addition, angiotensin stimulated cortisol biosynthesis in a fasciculata cell suspension in which angiotensin did not stimulate aldosterone production. Therefore, in human adrenal cell suspensions angiotensin appeared to act directly to stimulate cortisol synthesis by fasciculata cells. In normal subjects pre-treated with dexamethasone, angiotensin infusions failed to stimulate an increase in plasma cortisol. The physiological importance of angiotensin as a regulator of cortisol secretion remains, therefore, to be established.

Effects of indomethacin on uterine capillary permeability and blastocyst development in rabbits

Increased capillary permeability at implantation sites was demonstrated in rabbits by extravasation of intravascular blue dye on day 7 of pregnancy. Subcutaneous administration of indomethacin (Id, 8 mg/kg twice daily) on days 4-6 of pregnancy inhibited this uterine blueing response and appeared to reduce the size of implantation swellings. To test the latter observation blastocyst diameter and development of the embryonic disk were assessed at 144 hr post coitum. In females receiving indomethacin at the dose level which inhibited uterine blueing, blastocysts were significantly smaller than those from control females. Developmental staging of embryonic disks revealed only slight differences between the smaller (Id-treated) blastocysts and control blastocysts. No effect of Id was seen on ovarian function as judged by luteal weights and plasma progesterone and estradiol levels. Since the major biological effects of indomethacin are due to its inhibition of prostaglandin synthesis, it appears that prostaglandins may play a role in the uterine response to blastocyst stimulation and in the expansion of blastocysts in the rabbit.

Progesterone receptor in the rat anterior pituitary: effect of estrogen priming and adrenalectomy

The present study was done to determine if a progesterone receptor is present in rat pituitary. Cytosol was labeled with 3H-progesterone (3HP) or 3H-R5020 (3HR) and subjected to sucrose-glycerol density-gradient centrifugation. Serum progesterone was measured for correlation with progesterone receptor levels. Two 3HP-binding peaks (4S + 6S) were evident in uterine and pituitary cytosols. The 4S peak was eliminated by competition with unlabeled cortisol leaving a single 6S peak (progesterone receptor). Estradiol (E) priming of the male or female rat increased progesterone receptor levels in pituitary cytosol as demonstrated using 3HP and 3HR, and pituitary progesterone receptor bound 3HR with a higher affinity than 3HP. Following adrenalectomy of gonadectomized rats, progesterone receptor levels were increased in pituitary and uterine cytosol of both E-primed and unprimed groups. An inverse relationship was established between serum progesterone and progesterone receptor levels in the uterus and pituitary suggesting that stress-induced adrenal progesterone secretion significantly influences progesterone receptor levels in the rat. These results demonstrate an estrogen-inducible progesterone receptor in the rat pituitary with properties similar to those of the uterine progesterone receptor.

Prepartum serum hormone concentrations related to dystocia in Holstein heifers

Twelve Holstein heifers from a herd having a high incidence of dystocia were bled each day at 0730 h from 260 days gestation until parturition. The blood was analyzed for estradiol-17beta, estrone, 17-hydroxyprogesterone, progesterone, and corticosteroids. Six of the animals had dystocia. The concentrations of estradiol-17beta were lower and the concentration of progesterone higher in dystocial animals during the prepartum period from 23 to 12 days. The prepartum patterns of secretion of corticosteroid, estrone, and 17-hydroxyprogesterone did not change significantly in the two groups between days 23 and 12 prepartum. The prepartum difference in serum estradiol-17beta and progesterone concentration between normal and dystocial animals suggests that the timing of hormone changes in preparation for parturition is delayed and not as pronounced in dystocial animals.

Prevention of implantation by [D-Trp6-LH-RH in the rat: comparative study with the effects of large doses of HCG on pregnancy

Effect of large doses of [D-Trp6]-LH-RH and HCG on implantation of fertilized ova was examined in the rat. Subcutaneous administration of 6ug[D-Trp6]-LH-RH per day from days 1 to 5 of pregnancy by an implanted minipump completely prevented the implantation of fertilized ova associated with a dramatic reduction of plasma progesterone on days 4 and 8, with a slight reduction of estradiol on day 4. There was no balooning of the uterus in the exploratory laparatomy on days 8 and 14. Administration of 1000 U of HCG daily from days 1 to 5 partially prevented implantation and completely terminated gestation. However, plasma progesterone and estradiol levels did not differ from those in the control animals. Ovaries in the [D-Trp6]-LH-RH treated rats appeared to be the same in size as those of the control pregnant rats, whereas the ovaries of the HCG-treated rats were hypertrophied. The results suggest that [D-Trp6]-LH-RH prevents nidation through a mechanism different from that for the adverse effect of excess of HCG on pregnancy.

The pituitary-gonadal axis in spinal cord injury

Our study documented that serum levels of luteinizing hormone, follicle-stimulating hormone, testosterone, and estradiol in 14 of 15 males with spinal cord injury (SCI) were within the normal range of those of age-matched controls. One patient had gynecomastia with compensated gonadal insufficiency of undetermined etiology. Five males with SCI showed a normal rise in serum testosterone levels following stimulation with human chorionic gonadotropin. Testicular biopsy in one of two males with SCI showed spermatogenic arrest. One of the biopsies showed immunoglobulin G immunofluorescence around the seminiferous tubule; the other demonstrated immunoglobulin A immunofluorescence in the spermatogonia. These findings suggest that, if a high incidence of impaired spermatogenesis does occur in spinal cord-injured patients, it is unlikely to be secondary to hormonal imbalance.

Cyclic changes of cervical mucus enzymes related to the time of ovulation. I. Alkaline phosphatase

The concentration of alkaline phosphatase in cervical mucus was serially determined during a menstrual cycle in five normal ovulatory women and correlated with the time of ovulation as monitored by the basal body temperature and radioimmunoassay of serum lutenizing hormone (LH), progesterone, and estradiol. The activity of alkaline phosphatase decreased significantly at midcycle just prior to the LH surge and began to rise after ovulation. Self-detection of cervical mucus alkaline phosphatase may provide a practical method of ovulation prediction.

A simple method for the assay of eight steroids in small volumes of plasma

A simple method is described for the simultaneous radioligand assay of four delta5-3beta-hydroxysteroids adjacent to one another on the biosynthetic pathway (pregnenolone [1], 17alpha-hydroxypregnenolone, dehydroepiandrosterone and 5-androsterone-3beta, 17beta-diol), and their four delta4-3keto products (progesterone, 17alpha-hydroxyprogesterone, 4-androstene-3, 17-dione and testosterone). Two plasma aliquots are extracted and fractionated each for four steroids and individual corrections are made for losses. For fractionation, maximum use is made of the high resolution and reproducibility of celite minicolumns, using propylene glycol as stationary phase, and a discontinuous gradient of ethyl acetate in iso-octane as mobile phase. The fractions are then assayed in the appropriate radioligand end-assay system. Each assay was finally validated by demonstrating coincidence of peaks of immuno- and radioactive steroid in extracts of female plasma. Results in pre-pubertal girls and women in the follicular phase of the menstrual cycle suggest that the major change in adrenal steroid production at puberty may be an increase in 17, 20-desmolase activity. There appears to be little reversal of this change in adrenal function after ovariectomy.

A study of the use of intermittent serum luteinizing hormone, progesterone and oestradiol measurements for the detection of ovulation

The value of luteinizing hormone (LH), progesterone (P) and oestradiol (E2) in serum as an index of ovulation and corpus luteum function was studied in blood samples collected at infrequent intervals during the menstrual cycle from 19 healthy Thai women. A serum P level of more than 3 ng/ml was detectable in 70 to 80 per cent samples obtained between days 20 and 25 and a P peak and/or E2 peak (greater than 150 pg/ml) were found at this time in 85 to 94 per cent of the cycles. In not more than 26 per cent of the cycles was an LH peak (greater than 150 ng/ml-LER-907) detected when all results were considered. A significant P and/or E2 peak on day 22 or 23 occurred in more than 78 per cent of 25 to 33 day cycles, whereas, the P and/or E2 peak was detectable in only 50 per cent of the cycles lasting less than 25 or more than 33 days. The postovulatory serum P levels were the ones most consistently raised in patients studied over several consecutive cycles.

Temporal changes in circulating steroids during prostaglandin F2alpha induced abortion in the rat and rabbit

The serum levels of progesterone (delta4P), 20alpha-dihydroxyprogesterone (20alpha-DHP), pregnenolone (delta5P) and estrogens at different time intervals during Silastic-PVP-PGF2alpha tube induced midterm abortion were measured by radioimmunoassay in the rat and rabbit. The concentrations of delta4P and delta5P were significantly reduced but that of 20alpha-DHP was increased significantly as early as 20 hours after PGF2alpha treatment. Estrogen levels showed slight reduction in the rat but remained unchanged in the rabbit. The ratio of delta4P/20alpha-DHP recorded were 2.15 and 16.86 (pretreatment) and dropped to 0.08 and 0.37 (60 hours after insertion of Silastic-PVP-PGF2alpha tube) in the rat and rabbit, respectively. These findings suggest that the suppression of circulating delta4P by PGF2alpha might be the result of a reduced precursor (delta5P) pool size as well as changes in the enzymic systems responsible for the formation and conversion of delta4P. It is still to be determined if changes in estrogen levels in the rat have any bearing on abortion induced by PGF2alpha.

Primary culture and maintenance of steroid-secreting human placenatal monolayers

A simple method is described for primary culture and for maintenance of hormone-producing cells from normal human placenta. A consistent yield of cells was obtained and an average survival of 3 to 4 months in culture using 1 mm3 explants from the most vascular area of the placentas. These explants were placed in a variety of culture media in 30 ml flasks and incubated at 37 degrees C in an atmosphere of 5% CO2 and 95% air. The best yields in terms of cell growth were observed with Eagle's MEM (minimum essential medium) with supplements of horse serum and fetal calf serum or human cord serum. (Ham's F-10 with supplement of horse serum and fetal calf serum supports growth for the longest period and media containing human cord serum had the best yield of steroids.