Progesterone stimulates luteinizing hormone secretion by acting directly on the pituitary.

To determine if progesterone (P) does affect gonadotropin secretion by acting directly on the pituitary, six women with hypothalamic gonadotropin deficiency were studied. They were treated with 17 beta-estradiol (E2; 2 mg/day, orally) to induce P receptors and maintain constant plasma E2 levels during two 15-day periods separated by 1 month. GnRH was administered iv at a dose of 10 microgram/pulse every 90 min during the last 5 days of E2 treatment. Either P (400 mg/day) or a placebo was administered intravaginally in a cross-over randomized design during the 5 days of pulsatile GnRH therapy. A baseline study of pulsatile LH secretion was performed, with sampling performed every 10 min for 8 h. The sampling was then repeated on day 15 of each study period at the end of pulsatile GnRH administration. Plasma levels of E2 and P were measured every day during the 5 days of either GnRH and P or GnRH and placebo treatment. In the six patients, the observed apulsatile pattern of LH during the baseline study confirmed the diagnosis of complete gonadotropin deficiency. Plasma E2 levels were not significantly different at the time of each pulse analysis (288 +/- 61 vs. 252 +/- 77 pmol/L). The plasma P level achieved with the vaginal pessaries was 22 +/- 5 nmol/L. P treatment resulted in all cases in a significant increase in the mean plasma LH level (5.2 +/- 0.9 vs. 3.6 +/- 0.7 IU/L after GnRH plus placebo; P less than 0.001). Furthermore, LH pulse amplitude was significantly increased by P compared to placebo (3.1 +/- 0.3 vs. 1.4 +/- 0.1 IU/L, respectively; P less than 0.01). Mean plasma FSH levels were significantly increased by GnRH regardless of whether P or placebo was present. In conclusion, these data indicate that a short exposure to physiological levels of P in the range of early luteal phase levels has a stimulatory effect on LH secretion by acting directly at the pituitary level.

Angiotensin and adrenal steroidogenesis: study of 21-hydroxylase-deficient congenital adrenal hyperplasia.

The effects of angiotensin have been studied in four adult patients with the simple virilizing form of congenital adrenal hyperplasia due to 21-hydroxylase deficiency. They were treated with hydrocortisone (25 mg/day) throughout this investigation. Plasma ACTH was normal in three cases, and androstenedione was normal in all cases. However, urinary pregnanetriol, plasma 17-hydroxyprogesterone (17 OHP), aldosterone, and renin activity was increased. The patients were then submitted to three protocols: sodium depletion (10 meq Na/day) for 5 days, sodium repletion (200 meq Na/day) for 5 days, and angiotensin infusion (sufficient to maintain a pressor response) for 60 min. Urinary pregnanetriol, plasma 17 OHP, and androstenedione levels increased in all patients after sodium depletion and decreased after sodium repletion. Plasma ACTH levels were not modified by changes in the sodium balance. Furthermore, angiotensin infusion increased aldosterone and 17 OHP plasma concentrations without any change in the plasma ACTH level. This study shows the direct action of angiotensin on adrenal steroidogenesis, at least in 21-hydroxylase deficiency. It confirms that even in the simple virilizing form, combined treatment with glucocorticoids and mineralocorticoids helps to normalize plasma 17 OHP levels.

Stimulation of ovarian follicular maturation with pure follicle-stimulating hormone in women with gonadotropin deficiency.

According to the 2-cell theory, ovarian steroidogenesis requires the coordinate action of both FSH and LH. To evaluate the relative importance of these hormones in follicular maturation, a randomized cross-over study was performed in 10 women with complete gonadotropin deficiency (absence of pulsatile LH secretion and no LH response to LHRH). Five women were treated with highly purified FSH (LH bioactivity, 0.09%) and 3 months later with human menopausal gonadotropin (hMG; LH bioactivity, 65%), each given for 10 days at a daily dose of 225 IU FSH, im. The sequence was reversed in the other 5 women. hCG (5000 IU) was administered im 24 h after the last injection of FSH or hMG. Plasma estradiol (E2), estrone (E1), androstenedione (A), testosterone, LH, and FSH concentrations and urinary LH and FSH were measured daily by RIA. Ultrasonography was performed during each treatment and 2 days after each hCG injection. After FSH treatment, mean plasma and urinary FSH levels increased, mean plasma LH did not change, and urinary LH increased slightly but not significantly from 91 +/- 32 (SE) to 164 +/- 55 mIU/24 h (10(-3) IU/24 h). After hMG treatment, mean plasma and urinary LH and FSH levels increased accordingly. The mean basal plasma E2 [11 +/- 1 pg/mL (40 +/- 4 pmol/L)] and E1 [14 +/- 4 pg/mL (52 +/- 15 pmol/L)] levels increased after FSH treatment to 207 +/- 69 pg/mL (760 +/- 253 pmol/L) and 82 +/- 21 pg/mL (303 +/- 78 pmol/L), respectively (P less than 0.01), but plasma A did not change. In response to hMG, the mean plasma E2, E1, A, and testosterone levels increased more than during FSH treatment. Ultrasonography revealed multiple preovulatory follicles (greater than or equal to 16 mm) in 2 women after hMG and 1 woman after FSH treatment; therefore, hCG was not administered. In 3 women given FSH, hCG did not induce ovulation. hCG induced ovulation in 8 women given hMG and in 6 women given FSH, based on ultrasonography and plasma progesterone levels. Thus, in the presence of profound gonadotropin deficiency pharmacological doses of FSH, with minute LH contamination, are capable of stimulating ovarian follicular maturation, underlining the key role of FSH in folliculogenesis.

Comparative effects of cyproterone acetate or a long-acting gonadotropin-releasing hormone agonist in polycystic ovarian disease.

A randomized cross-over study was done to compare the therapeutic efficacy of cyproterone acetate (CPA) and a depot preparation of the LHRH superagonist (DTrp6-LHRH) in 10 patients with polycystic ovarian disease (PCO). All patients were treated with both agents (50 mg/day CPA, orally and (3 mg DTrp6-LHRH, im, approximately once a month) for 3 months, the 2 treatment periods being separated by 6 months. Both treatments resulted in marked clinical improvement, with diminished acne and seborrhoea and normalization of ovarian size by ultrasonographic criteria. In response to CPA treatment, basal plasma gonadotropin levels decreased, but the response to a LHRH test was not completely suppressed. Plasma estradiol, estrone, testosterone, and androstenedione levels significantly decreased, but urinary 3 alpha-androstanediol and plasma dehydroepiandrosterone sulfate levels did not change significantly. In contrast to CPA treatment, both basal and stimulated gonadotropin levels were completely suppressed after 3 weeks of treatment with DTrp6-LHRH. After a slight initial evaluation on day 2, plasma estrogen and androgen levels, with the exception of dehydroepiandrosterone sulfate fell into the castrate range urinary 3 alpha-androstanediol excretion decreased significantly. Thus, in patients with PCO, LHRH-A induced more complete gonadotropin inhibition than did CPA. After cessation of either therapy, the disease rapidly recurred.

Failure of combined follicle-stimulating hormone-testosterone administration to initiate and/or maintain spermatogenesis in men with hypogonadotropic hypogonadism.

In men with hypogonadotropic hypogonadism, prolonged treatment with LH and FSH induces spermatogenesis. To compare the respective role of exogenous testosterone and intratesticular testosterone on the induction and maintenance of spermatogenesis, 10 men with hypogonadotropic hypogonadism and without history of cryptorchidism were studied. They were treated with human gonadotropins (hMG; 150 IU FSH and LH and 1500 IU hCG, im, three times weekly) or pure FSH (150 IU, im, three times a week) and testosterone (T: 250 mg, im, once a week). Five men were treated first with hMG-hCG and then with pure FSH plus T. The other five men started with pure FSH plus T. Each treatment period lasted 24 months. In all men, hMG-hCG induced spermatogenesis after 24 months, with normal motility and quality. The combination of pure FSH and T was not able to induce spermatogenesis after 24 months. In addition, sperm count dropped dramatically to 0.3 +/- 0.1 x 10(6)/mL within 3 months and to 0 after 6 months when pure FSH and T followed [corrected] hMG-hCG. Plasma T levels were increased by both treatments, but significantly more after pure FSH and T (35.3 +/- 5.2 nmol/L) than after hMG-hCG (20.4 +/- 5.2 nmol/L; P < 0.05). Plasma estradiol levels after treatment with pure FSH and T were also increased, but the difference from those obtained during hMG-hCG treatment was not significant. In conclusion, in men with complete gonadotropin deficiency, FSH and exogenous T are not able to induce spermatogenesis. Furthermore, spermatogenesis induced by LH plus FSH (hMG-hCG) cannot be maintained when exogenous T replaced LH in the regimen. Thus, exogenous T is unable to replace LH (and intratesticular T) to induce spermatogenesis. These data are noteworthy in the prospect of male contraception after a complete blockade of gonadotropin activity.

Even after priming with ovarian steroids or pulsatile gonadotropin-releasing hormone administration, naltrexone is unable to induce ovulation in women with functional hypothalamic amenorrhea.

In functional hypothalamic amenorrhea (HA), it has been reported that administration of opioid receptor antagonists restores gonadotropin secretion and ovarian function. However, endogenous opioids may modulate gonadotropin secretion only in the presence of ovarian steroids. To further study these conflicting results, a group of nine women with secondary functional HA who wished to become pregnant were studied. The opiate antagonist naltrexone (Nal; 100 mg/day) was administered for two 30-day periods, starting on either day 22 (Nal 1) of a well characterized replacement regimen with estradiol (E2) and progesterone (P), or on day 22 (Nal 2) of the luteal phase induced by exogenous pulsatile GnRH administration (10 micrograms/pulse, iv, every 90 min). Plasma LH and FSH were measured every 10 min for 8 h before treatment and on day 12 of each treatment period (Nal 1, pulsatile GnRH, and Nal 2). Ovulation was monitored during each treatment. Plasma E2 levels were measured on days 12 and 22, and P levels on day 22 of each treatment. During exogenous E2 and P administration, plasma steroid levels reached luteal phase levels. However, during Nal 1, plasma E2 levels fell to prestudy levels and remained low. No follicular growth occurred, and the pulsatile study showed pretreatment frequency, amplitude, and mean plasma levels of LH. On day 12 of pulsatile GnRH administration, plasma E2 levels increased, and LH and FSH pulses followed each GnRH pulse during the frequent sampling study. Ovulation occurred in all women during pulsatile GnRH treatment. During Nal 2 treatment, plasma E2 levels returned to prestudy levels without follicular growth, and the pulsatile study was similar to those prior treatment and during Nal 1 administration. In conclusion, Nal, started during priming either with exogenous E2 and P treatment or gonadotropin stimulation induced by pulsatile GnRH administration, was unable when continued alone to initiate or maintain gonadotropin secretion in women with HA. Thus, the exclusive role of opioids in HA and the effect of Nal even in the presence of ovarian steroids are questionable.

Androgen insensitivity in oligospermic men: a reappraisal.

Androgen insensitivity has been reported to be present in as many as 40% of patients with severe oligospermia. In order to evaluate further the role of androgen resistance in male infertility we studied 24 men with severe oligospermia. Plasma T and LH were measured by RIA and the T X LH product was calculated. Fibroblasts were grown from genital skin obtained during testicular biopsies and androgen receptor maximal binding capacity (BMAX) and affinity (KD) were measured in fibroblast monolayers. Pubic skin 5 alpha-reductase activity, an androgen-dependent enzyme, was measured in skin homogenates. Plasma T values were in the upper normal range [7.0 +/- 1.7 (SEM) ng ml-1] whereas the T X LH product was high (greater than 50) in only six patients. Mean BMAX and KD values for the androgen receptor were normal [BMAX: 788 +/- 259 fmol mg DNA-1 (patients, n = 20), 726 +/- 227 (normal men, n = 20), and KD: 0.27 +/- 0.24 (patients, n = 20), 0.18 +/- 0.09 (normal men, n = 15), respectively]. However, four men had supranormal KD values. The mean BMAX was also normal when the group of men with sperm densities below 10(6) per ejaculate was considered separately. Public skin 5 alpha-reductase activity was normal in all but four patients (patients: 177.1 +/- 91 fmol/mg skin/h, n = 30, normal men: 210 +/- 45, n = 20 patients). In conclusion, androgen receptor BMAX levels were normal in all patients studied, regardless of the sperm density and the T X LH product. Pubic skin 5 alpha-reductase activity was also normal in all but four patients. In these four patients, a qualitative defect of the androgen receptor cannot be excluded. In this group of patients with severe oligospermia, infertility did not seem to be related to quantitative abnormality of the androgen receptor as was previously reported.

Differing responses of plasma bioactive and immunoreactive follicle-stimulating hormone and luteinizing hormone to gonadotropin-releasing hormone antagonist and agonist treatments in postmenopausal women.

Plasma bioactive (B) and immunoreactive (I) FSH and LH were measured every 10 min for 8 h in the same postmenopausal women in a three-phase study: 1) during normal pulsatile gonadotropin secretion (basal study; n = 8), 2) 8 h after a single injection of a GnRH antagonist (5 mg Nal-Glu, sc; n = 5), and 3) 21 days after a GnRH agonist injection (D-Trp6, 3.75 mg depot preparation, im; n = 7). I-FSH and I-LH were measured by monoclonal antibody immunoradiometric assays. B-FSH and B-LH were measured in selected samples with the immature rat granulosa cell and mouse interstitial cell assays, respectively. Significant pulsatility of B- and I-FSH and LH was demonstrated in the basal samples, but only the B/I ratio of LH was slightly elevated within the secretion peaks. After GnRH antagonist treatment, I-FSH decreased from a mean pretreatment level of 55.7 +/- 7.8 IU/L by 26% (P less than 0.001), and B-FSH from 313.8 +/- 61.9 IU/L by 44% (P less than 0.01). The B/I ratio decreased from 6.4 +/- 1.7 to 4.5 +/- 1.0 (P less than 0.05). After agonist treatment, the I- and B-FSH levels decreased by 92% and 83% (P less than 0.0001), respectively, but the B/I ratio increased to 17.3 +/- 4.7 (P less than 0.05). The concentrations of I- and B-LH decreased by 75% and 80%, respectively (P less than 0.001), after antagonist treatment. After agonist treatment, I-LH decreased by 92%, and B-LH by 93% (P less than 0.0001). No changes in the B/I ratios of LH were found after either treatment. In conclusion, no changes were found in the quality of circulating LH during the treatments, whereas the antagonist treatment decreased and the agonist treatment increased the B/I ratio of FSH. These findings provide further evidence that the qualitative responses of FSH and LH to treatment with the same GnRH analog are different, and that the suppressive mechanisms of GnRH antagonist and agonist action on gonadotropin secretion are different.

Effects of human recombinant luteinizing hormone and follicle-stimulating hormone in patients with acquired hypogonadotropic hypogonadism: study of Sertoli and Leydig cell secretions and interactions.

UNLABELLED: Experimental data suggest that FSH-stimulated Sertoli cells can enhance LH-induced Leydig cell testosterone (T) production. The function of Leydig and Sertoli cells can be selectively studied by using recombinant human LH (rhLH) and recombinant human FSH (rhFSH) in patients with complete gonadotropin deficiency. The aim of the present study was to assess the secretion of testicular T, estradiol (E2), and inhibin B and the physiological relevance of the Sertoli-Leydig cell interaction in man. For that purpose, six patients with acquired complete hypogonadotropic hypogonadism received the following treatments for three periods of 1 month in a random order: 1) rhLH, 900 IU/day sc; 2) rhFSH, 150 IU/day sc; and 3) combined rhLH/rhFSH treatments. Each treatment period was separated by a washout period of 15 days. Plasma LH, FSH, T, E2, and inhibin B were measured before and every 10 days during each treatment. During rhLH administration, mean plasma LH levels rose significantly from 0.4 +/- 0.2 IU/L to 11.7 +/- 1.2 IU/L (P < 0.01) and plasma FSH levels did not change. rhFSH administration induced a significant increase in plasma FSH levels (from 0.5 +/- 0.4 to 12.1 +/- 1.4 IU/L; P < 0.01), whereas mean plasma LH levels remained low. Mean plasma E2 levels were unchanged during rhFSH treatment, but they increased significantly during rhLH from 22 +/- 4 to 54 +/- 8 pmol/L (P < 0.01) and during rhLH plus rhFSH administration. rhFSH treatment induced a sustained elevation of mean plasma inhibin B levels from 58 +/- 13 to 175 +/- 25 pg/mL (P < 0.01), similar to the increase occurring during rhFSH plus rhLH administration. In contrast, mean plasma inhibin B levels did not increase during rhLH administration. Finally, a similar and significant increase in mean plasma T levels occurred during both rhLH and rhLH plus rhFSH treatment from 0.9 +/- 0.3 to 5.4 +/- 0.7 nmol/L (P < 0.01) and from 1.0 +/- 0.4 to 6.0 +/- 0.9 nmol/L (P < 0.01), respectively. In contrast, during rhFSH treatment mean plasma T levels remained unchanged when compared with baseline. IN CONCLUSION: 1) the increase of plasma E2 induced by rhLH and the absence of effect of rhFSH confirm that Leydig cells are the major site of testicular E2 production in man; 2) the secretion of inhibin B is increased by rhFSH and not by rhLH, and, thus, Sertoli cells seem to be the main source of inhibin B production; and 3) the increase of plasma T induced by rhLH is not enhanced by rhFSH. These results suggest that the stimulatory effect of FSH on Leydig cell steroidogenesis by a Sertoli cell paracrine factor does not seem to play a major physiologic role in man.

Free luteinizing-hormone beta-subunit in normal subjects and patients with pituitary adenomas.

Most clinically nonfunctioning pituitary adenomas (NFPA) are found to be gonadotropinomas when assessed by immunocytochemistry. However, they are rarely associated with increased basal plasma levels of FSH, LH and/or alpha-subunit. It has been claimed that the paradoxical free LHbeta response to TRH may be a useful clinical tool for determining the gonadotropic nature of NFPA. We used a very specific and sensitive immunoradiometric assay (IRMA) for free LHbeta measurement and another specific IRMA to check the absence of free CGbeta, to study normal subjects and 26 patients with NFPA. Basal plasma levels of LHbeta were undetectable in normal men and premenopausal women in the early follicular phase. In contrast, normal postmenopausal women had increased basal plasma LHbeta, parallel to dimeric LH and alpha-subunit levels. In healthy subjects, stimulation with GnRH elicited an increase in LHbeta while TRH was ineffective. In patients with NFPA, LHbeta hypersecretion was found basally and/or after stimulation with TRH in 3 of 16 men, 3 of 5 premenopausal women, and 1 of 5 postmenopausal women, i.e. 7 of 26 patients (26%). In 3 of these 7 cases, alpha-subunit and/or FSH levels were also increased. The LHbeta measurement was thus truly informative on the gonadotropic nature of NFPA in only 4 out of 26 cases (15%). In addition, increased LHbeta levels and/or a positive response of free LHbeta to TRH was observed in 3 patients with pure prolactinomas but in no patients with GH-secreting adenomas. Thus, using this very sensitive and specific IRMA, free LHbeta measurement is rarely helpful for determining the gonadotropic nature of NFPA.

Panhypopituitarism as a model to study the metabolism of dehydroepiandrosterone (DHEA) in humans.

The physiological importance and therapeutical interest of dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are still controversial. Panhypopituitarism is characterized by the absence of secretion of adrenal and gonadal steroids and thus the production of their metabolites. The conversion of DHEA given orally into delta 5 derivatives, androgens, androgen metabolites, and estrogens was studied in ten patients with complete panhypopituitarism. Sex steroid therapy was withdrawn for at least 2 months. Each patient received, at 1-month intervals and in a random order, two single oral doses of DHEA (50 mg and 200 mg) and placebo. During each treatment, urine samples were collected for 24 h, and blood samples were drawn at hourly intervals for 8 h. In patients with pituitary deficiency, plasma DHEA and DHEAS were not detectable and increased, with the 50 mg dose, up to levels observed in young adults. The administration of 200 mg of DHEA induced an increase of both steroids to supraphysiological plasma levels. A small increase of delta 5-androstenediol was observed. In contrast, the increase of plasma delta 4-androstenedione was important and dose dependent. DHEA was also converted into the potent sex steroid testosterone (T). The administration of a 50 mg dose of DHEA restored plasma T to levels similar to those observed in young women. The 200 mg dose induced an important increase of plasma T, slightly below the levels observed in normal men. The increase of plasma dihydrotestosterone levels was small at both doses of DHEA, in contrast with the large conversion of DHEA into androsterone glucuronide and androstanediol glucuronide. Finally, DHEA administration induced a significant and dose dependent increase of plasma estrogens and particularly of estradiol. In conclusion, this short term study demonstrates that: 1) panhypopituitarism is a model of interest to study the metabolism of DHEA; 2) in the absence of pituitary hormones and of adrenal and gonadal steroids, DHEA given orally is mainly converted into delta 4 derivatives, which in turn are strongly metabolized into 5 alpha-3keto-reduced steroids; 3) a significant increase of sex active hormones was observed in plasma after 200 and even 50 mg of DHEA. Thus, biotransformation of DHEA into potent androgens and estrogens may explain several of the reported beneficial actions of this steroid in aging people.

Plasma 3 beta-hydroxy-delta 5-steroids in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency.

There is little information about the plasma concentrations of 3 beta-hydroxy-delta 5-steroids (delta 5-steroids) in untreated patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. To further study the delta 5 pathway, we measured plasma levels of delta 5- and delta 4-steroids in 21 adult patients with different degrees of 21-hydroxylase deficiency (11 salt-wasters, 5 simple virilizers, and 5 patients with the nonclassical form of the disease). In all patients, investigations were performed after withdrawal of steroid treatment for at least 10 days. In addition, catheterization of gonadal and adrenal veins was performed in two salt-wasting male patients displaying bilateral testicular tumors to study adrenal secretion of delta 5- and delta 4-steroids. In one of them, surgical resection of the intratesticular adrenal rests gave the opportunity to measure 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) activity. In all untreated patients, an increase in plasma delta 4-steroids was observed. In contrast, although plasma levels of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) were not significantly modified in simple virilizers, a paradoxical decrease in all delta 5-steroids was observed in salt-wasters. Catheterization of the adrenal veins confirmed the decrease in delta 5-steroids, particularly DHEA and DHEAS. The androstenedione/DHEA ratio was increased in all patients proportionally to the severity of the disease, suggesting an increase in adrenal 3 beta HSD. In vitro analysis of 3 beta HSD activity showed a 4-fold increase in intratesticular adrenal tissue compared to that in normal adrenals. A positive correlation between the androstenedione/DHEA ratio and plasma ACTH levels was observed, suggesting a long term stimulatory effect of ACTH on 3 beta HSD. Angiotensin-II could have an additive effect on ACTH-induced 3 beta HSD activity.

The antigonadotropic activity of progestins (19-nortestosterone and 19-norprogesterone derivatives) is not mediated through the androgen receptor.

To further study the mechanism of the antigonadotropic activity of progestins, the effects of a 19-nortestosterone derivative, norethisterone acetate (NETA), and a 19-norprogesterone derivative, nomegestrol acetate (NOMA), were compared. The aim was to assess whether their action is exerted via the androgen receptor. Ten healthy postmenopausal women were treated for five monthly periods of 24 days separated by 10 days in a randomized cross-over design. Transdermal estradiol, Estraderm TTS (25 micrograms; one patch every 3 days), was given from days 1-24 during the five periods. On the last 12 days, of each estradiol treatment, they all received a placebo, NOMA (5 mg/day), NOMA in association with the nonsteroidal antiandrogen, flutamide (FLU; 250 mg, twice a day), NETA (10 mg/day), or NETA plus FLU. On the other hand, three castrated patients with complete androgen insensitivity (CAI) received NOMA and NETA for two periods of 12 days separated by 3 weeks. In postmenopausal women, the effects of NOMA and NETA on metabolic parameters were studied. Only NETA decreased high density lipoprotein cholesterol. Plasma LH, FSH, and estradiol were measured during each treatment period. A significant decrease in mean plasma LH and FSH levels and their responses to exogenous GnRH was observed with NOMA and NETA treatments compared to placebo (P < 0.001). The pulsatile frequency, but not the amplitude, of LH was significantly decreased during both treatments. Interestingly, the effects of both progestins on gonadotropins were not antagonized by FLU administration. In the patients with CAI, the pulsatile study of gonadotropins was performed before and on day 12 of NOMA and NETA treatments. As in postmenopausal women, both progestins induced similar decreases in LH and FSH. In conclusion, a 19-nortestosterone derivative, NETA, and a 19-norprogesterone derivative, NOMA, have similar antigonadotropic activities. This effect, not antagonized by FLU and observed in patients with CAI, is not mediated via the androgen receptor. The absence of deleterious effects of 19-norprogesterone derivatives on metabolic parameters should favor the therapeutic use of these compounds.

Antimüllerian hormone in patients with hypogonadotropic hypogonadism.

Antimullerian hormone (AMH) is produced by immature Sertoli cells until pubertal maturation. At puberty, elevation of serum testosterone correlates with a decrease in serum AMH. To further investigate the hormonal control of AMH secretion, serum AMH levels were measured in 20 normal men (20-60 yr), in 12 patients (19-30 yr) with congenital hypogonadotropic hypogonadism (CHH), and in 18 patients (19-65 yr) with acquired hypogonadotropic hypogonadism (AHH) either untreated or during testosterone or human chorionic gonadotropin (hCG) therapy. Mean serum AMH levels in normal adult men were low (20+/-4.9 pmol/L). In untreated CHH patients, mean serum AMH levels were significantly higher than in normal men (292+/-86 pmol/L, P < 0.001) and were similar to those previously reported in prepubertal boys. In men with AHH, mean serum AMH levels were also significantly increased (107+/-50 pmol/L; P < 0.01) when compared with healthy men but were less than in men with CHH. In addition, in 10 patients treated for prostate cancer, a modest but significant increase of serum AMH (from 11.4 +/-5.7 pmol/L to 49+/-9.9 pmol/L; P < 0.01) was observed 12 months after suppression of the gonadal axis with the GnRH agonist Triptorelin (3.75 mg IM once a month). Plasma testosterone (T) and serum AMH levels were measured at baseline and at 3 and 6 months in 10 HH patients (6 CHH and 4 AHH) treated with hCG (1500 IU/twice weekly for 6 months) and in 8 HH (4 CHH and 4 AHH) patients treated with T (T enanthate 250 mg/3 weeks for 6 months). hCG treatment induced an increase of plasma T (from 1.0+/-0.7 to 11+/-2.4 and 19+/-4.8 nmol/L, at 3 and 6 months respectively) associated with a dramatic decrease of serum AMH (from 314+/-93 to 56+/-30 and 17+/-4.3 pmol/L). The similar increase in plasma T levels (from 1.4+/-1.0 to 15.6+/-4.2 and 23+/-6.2 ng/mL) obtained with exogenous T induced a lesser decrease of serum AMH (from 221+/-107 pmol/L to 114+/-50 and 66+/-17 pmol/L, at 3 and 6 months respectively). In conclusion, high plasma AMH levels in CHH patients are related to the absence of pubertal maturation of Sertoli cells. The high AMH levels in AHH and its increase after Triptorelin-induced gonadotropin deficiency suggest that the suppression of AMH is a reversible phenomenon. Finally, the inhibition of AMH production by Sertoli cells is induced by intratesticular T.

The postmenopausal ovary is not a major androgen-producing gland.

It is currently believed that the postmenopausal ovary remains a gonadotropin-driven, androgen-producing gland. However, the adrenal contribution to circulating androgen levels may explain some conflicting results previously reported. In addition, the steroidogenic potential and gonadotropin responsiveness of the postmenopausal ovary have not been recently reassessed. Plasma T, bioavailable T, free T, androstenedione (Adione), and dehydroepiandrosterone sulfate levels were measured in postmenopausal or ovariectomized women with complete adrenal insufficiency, compared with women with intact adrenals. A stimulation human chorionic gonadotropin test (on d 0, 3, and 6) was performed in postmenopausal women with adrenal insufficiency. Dexamethasone was administered for 4 d in postmenopausal women with intact adrenals. Intraovarian T and androstenedione were also measured in homogenates of ovarian tissue from postmenopausal women. Immunocytochemistry was performed on postmenopausal ovaries and premenopausal controls to detect the presence of steroidogenic enzymes (P-450 aromatase, P-450 SCC, 3beta HSD, and P-450 C17) and gonadotropin receptors. Plasma androgen levels were below or close to the limit of the assay in all women with adrenal insufficiency. They were similar in postmenopausal and oophorectomized women with normal adrenals. No hormonal changes were observed after human chorionic gonadotropin injections in women with adrenal insufficiency. In contrast, a dramatic decrease of all steroids was observed after dexamethasone administration in postmenopausal women with intact adrenals. Intraovarian T and androstenedione levels were negligible in postmenopausal ovarian tissue. P-450 aromatase was absent from the 17 ovaries studied, and the enzymes for androgen biosynthesis were either absent (n = 13) or present in very low amounts (n = 4). In all the postmenopausal ovaries, FSH and LH receptors were completely absent. In the absence of adrenal steroids, postmenopausal women have no circulating androgens. This result is consistent with the immunocytochemical studies showing the almost constantly absent steroidogenic enzymes and LH receptors in the postmenopausal ovary. Thus, the climacteric ovary is not a critical source of androgens. The arrest of androgen secretion after menopause may impact significantly on women's health.

Measurement of plasma free luteinizing hormone beta-subunit in women.

Little is known about the physiological secretion of the free beta-subunit of LH (LHbeta). The aim of this study was to compare in women the secretion of LHbeta, using sensitive and specific two-site immunoassays, with dimeric LH and the free common alpha-subunit (FAS). The LHbeta assay does not recognize the dimeric LH and cross-reacts only with free hCG beta-subunit (CGbeta). Thus, all of the plasma samples were also tested with a highly specific immunoradiometric assay for free CGbeta. Molar concentrations (i.e. picomoles per L) were used to compare the plasma levels of LH and its free subunits. Plasma LH, LHbeta, FAS, and CGbeta levels were measured in five normally cycling women during the early follicular phase and the ovulatory peak of LH. The pulsatile profiles of LH, LHbeta, FAS, and CGbeta were studied in five postmenopausal women before and 21 days after injection of a depot preparation of the GnRH agonist D-Trp6 (3.75 mg, im) and in five women with functional hypothalamic amenorrhea (FHA), i.e. low plasma LH levels, during pulsatile GnRH administration (20 microg/pulse, 90 min, sc). Afterward, one of the patients with FHA received a single sc injection of 1350 U recombinant human LH, and plasma LH, LHbeta, FAS, and CGbeta levels were measured and compared with the high plasma levels of one postmenopausal woman. In cycling women, basal plasma LHbeta and CGbeta levels were below the detection limit of the assays (1.34 and 0.65 pmol/L, respectively), and plasma FAS levels were 13.60 +/- 0.13 pmol/L. During the LH surge, there was a parallel increase in LH, LHbeta, and FAS. Plasma CGbeta levels remained undetectable. In normal postmenopausal women, basal plasma dimeric LH, LHbeta, and FAS levels were increased in parallel, and their pulsatile profiles were similar, without measurable plasma CGbeta levels. After D-Trp6 administration, plasma LH and LHbeta levels were completely suppressed, whereas plasma FAS levels increased, and plasma CGbeta remained below 0.65 pmol/L. In FHA women, basal plasma levels of LH and FAS were low, without detectable LHbeta and CGbeta levels. During pulsatile GnRH administration, LHbeta became detectable, and pulses were synchronous with those of LH and FAS. The secretion of LH and LHbeta was almost equimolar. Plasma CGbeta levels remained undetectable. In the patient with FHA, administration of recombinant human LH increased only plasma LH levels, whereas plasma LHbeta and FAS levels remained very low. In conclusion, when the production of dimeric LH increases, a concomitant, parallel, and almost equimolar hypersecretion of uncombined and biologically inactive LHbeta occurs. Like the alpha-subunit, LHbeta may be secreted in the dissociated free form. This can lead to pitfalls during clinical investigations if assays of free CGbeta display some cross-reaction with free LHbeta.

The antigonadotropic activity of a 19-nor-progesterone derivative is exerted both at the hypothalamic and pituitary levels in women.

We have previously shown in postmenopausal women that a 19-nor-progesterone derivative, nomegestrol acetate (NOMA) had a strong antigonadotropic activity and that this effect was not mediated via the androgen receptor. The aim of the present study was to further assess the action of this progestin on gonadotropin secretion in women. To demonstrate at which level of the hypothalamo-pituitary-ovarian axis the gonadotropin inhibition was exerted, 10 normally cycling (NC) women, 3 women with a gonadotropin-independent ovarian function [McCune-Albright (MCA) syndrome], and 5 women with functional hypothalamic amenorrhea (FHA) participated in the study. NC women were treated orally with 5 mg NOMA for 21 days, after one control cycle. Plasma estradiol (E2) and progesterone, LH, and FSH levels were measured during each cycle. A frequent sampling study (every 10 min for 4 h), followed by a classic GnRH test (100 microg, i.v.), was performed on day 11. Women with MCA were studied before, during NOMA, and after long-acting GnRH agonist administration. In women with FHA, pulsatile GnRH (20 microg s.c., every 90 min) was given for two cycles with or without NOMA (5 mg for 21 days). In all NC women, ovulation was suppressed by NOMA. Mean plasma LH levels, LH pulse frequency, and the LH response to exogenous GnRH were significantly decreased. In MCA, neither NOMA nor GnRH agonist modified multiple ovarian cysts on ultrasound or plasma E2, levels which remained elevated, ruling out a direct ovarian effect. In FHA, pulsatile GnRH administration recreated a normal ovulatory menstrual cycle. Addition of NOMA prevented the increase of plasma E2, decreased the amplitude of LH pulses, and prevented ovulation. In view of this unexpected action of NOMA at the pituitary level, seven samples of normal human female pituitaries were tested for the presence of progesterone receptor (PR) using a double labeling immunocytochemical technique. The presence of PR was detected in the seven human pituitary tissues. In addition, PR was found to be expressed only in gonadotroph cells. In conclusion, NOMA, a 19-nor-P derivative, has a potent antigonadotropic activity exerted at the hypothalamic level, inhibiting ovulation in NC women. In women with FHA, NOMA decreased the gonadotropin stimulation induced by pulsatile GnRH administration. According to the presence of PR in gonadotroph cells of normal human pituitaries, 19-nor-progesterone derivatives may also act on the gonadotropin secretion at the pituitary level.

Mifegyne (mifepristone), a new antiprogestagen with potential therapeutic use in human fertility control.

PIP: Animal and human volunteer research involving the hormone antagonist Mifegyne (mifepristone) is reviewed. Studies in animals and humans show that the potent antiprogesterone, Mifegyne, causes pregnancy interruption by acting directly at the level of the endometrium. Pharmacokinetic studies indicate that gastrointestinal absorption is low (25%), but subcutaneous and intramuscular routes do not fare better than does oral administration. Experimental studies in women testing for antiprogesterone effects indicate that mifegyne does not affect menstrual cycle length in women with regular ovulatory cycles, except when using the highest doses (600 mg). Mifegyne inhibits gonadotrophin secretion in a dose-dependent way. In humans, mifegyne has some progestomimetic activity in the endometrium in the absence of progesterone. Researchers know that larger doses of mifegyne than those sufficient to induce uterine bleeding are required to cause antiglucocorticosteroid effects. Studies demonstrate that in 18% of patients studied the only significant side effect is prolonged uterine bleeding. In addition, mifegyne fails to cause an abortion in 15% of the cases. The success rate is 85% when mifegyne is given prior to the 5th week of amenorrhea. Due to the occurrence of failed abortions and prolonged uterine bleeding in some women, researchers advise close medical supervision. An added effect of mifegyne is that in both animal and human studies it is effective in inducing labor. Preliminary studies suggest that mifegyne taken once a month only on the expected date of individual menses could be used as a safe and effective form of fertility control.^ieng

Steroid control of gonadotropin secretion.

Current knowledge about the mechanism and site of action of estradiol (E2) and progesterone (P) during the menstrual cycle and the physiological role of androgens is reviewed. In normal women, the positive feedback effect of E2 at the pituitary level is the principal event of the follicular phase inducing the LH surge. P, by its negative feedback at the hypothalamic level and by its positive feedback at the pituitary level regulates GnRH and LH secretion during the luteal phase. Androgens do not directly play a role in gonadotropin regulation.

Late luteal administration of the antiprogesterone RU486 in normal women: effects on the menstrual cycle events and fertility control in a long-term study.

Twelve regularly cycling women, with contraindications to other methods of contraception, received RU486 (Roussel UCLAF, Romainville, France), once a month as a method of fertility control. The study was designed for 18 consecutive cycles. Each patient recorded basal body temperature, detected urinary luteinizing hormone peak, and collected saliva samples during each luteal phase for progesterone (P) determinations. A single dose of RU486, 600 mg, was given on the day before the expected date of the menses and 8 days later in case of continuing pregnancy after the first dose. Blood samples were collected for estradiol, P, and beta-human chorionic gonadotropin analyses on these two occasions. The compliance was poor and the results of only 137 cycles were obtained. The menstrual cyclicity was not significantly modified during this long-term study. Of the 137 cycles, 22 pregnancies occurred (16%), and 4 (18.2%) were not interrupted by the second dose of RU486. Thus, because of the high failure rate, use of RU486 at the time of the natural P withdrawal cannot be advocated as a "once-a-month" contragestive agent.