Role of endogenous opiates in the expression of negative feedback actions of androgen and estrogen on pulsatile properties of luteinizing hormone secretion in man.

We have tested the participation of endogenous opiate pathways in the negative feedback actions of gonadal steroids on pulsatile properties of luteinizing (LH) hormone release in normal men. To this end, sex steroid hormones were infused intravenously at dosages that under steady state conditions selectively suppressed either the frequency or the amplitude of the pulsatile LH signal. The properties of pulsatile LH secretion were assessed quantitatively by computerized analysis of LH series derived from serial blood sampling over 12 h of observation. When the pure (nonaromatizable) androgen, 5-alpha-dihydrotestosterone, was infused continuously for 108 h at the blood production rate of testosterone, we were able to achieve selective inhibition of LH pulse frequency akin to that observed in experimental animals after low-dosage androgen replacement. Under these conditions, serum concentrations of testosterone and estradiol-17 beta did not change significantly, but serum 5 alpha-dihydrotestosterone concentrations increased approximately two- to threefold, with a corresponding increase in levels of its major metabolite, 5 alpha-androstan-3 alpha, 17 beta-diol. In separate experiments, the infusion of estradiol-17 beta at its blood production rate over a 4.5-d interval selectively suppressed LH pulse amplitude without influencing LH pulse frequency. Estrogen infusion increased serum estradiol-17 beta levels approximately twofold without significantly altering blood androgen concentrations. We then used these schedules of selective androgen or estrogen infusion to investigate the participation of endogenous opiates in the individual inhibitory feedback actions of pure androgen or estrogen on pulsatile LH release by administering a potent and specific opiate-receptor antagonist, naltrexone, during the infusions. Our observations indicate that, despite the continuous infusion of a dosage of 5 alpha-dihydrotestosterone that significantly suppresses LH pulse frequency, co-administration of an opiate-receptor antagonist effectively reinstates LH pulse frequency to control levels. Moreover, during the infusion of a suppressive dose of estradiol-17 beta, opiate receptor blockade significantly augments LH pulse frequency and increases LH peak amplitude to control levels. Thus, the present studies in normal men demonstrate for the first time that the selective inhibitory action of a pure androgen on LH pulse frequency is effectively antagonized by opiate-receptor blockade. This pivotal observation indicates that opiatergic and androgen-dependent mechanisms specifically and coordinately control the hypothalamic pulse generator for gonadotropin-releasing hormone (GnRH)

Preservation of androgen secretion during estrogen suppression with aminoglutethimide in the treatment of metastatic breast carcinoma.

We evaluated the comparative effects of aminoglutethimide (AG) on androgen and estrogen levels estrone ([E1], estradiol [E2], plasma dehydroepiandrosterone-sulfate [DHEA-S], testosterone [T], dihydrotestosterone [DHT], delta 4-androstenedione [delta 4-A]), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prolactin in postmenopausal patients with breast cancer randomly allocated to either AG treatment or bilateral surgical adrenalectomy as a control group. In response to either treatment, the plasma levels of E1 fell 62-75% (P less than 0.001) and urine E1 85.7-88.7% (P less than 0.001) in all study days over a 12-wk period. Similarly, the concentrations of E2 in plasma and urine fell 40-72% without statistically significant differences between the two treatment modalities. The relatively weak androgen, DHEA-S, was reduced by 92% (877.3 +/- 184.6 to 71.8 +/- 14.5 ng/ml) at 12 wk in women treated with AG, but suppressed nearly 99% (1,151 +/- 262 to 5.8 +/- 3.3 ng/ml) in adrenalectomized women. At all time points after treatment, the DHEA-S levels were significantly higher in patients receiving AG. Plasma concentrations of the potent androgens, T and DHT, were also relatively preserved during AG treatment. T levels were never significantly reduced by AG, and DHT concentrations were decreased only at the 4th wk to a maximum of 20%. delta 4-A levels fell 56% in response to this drug only on the 12th wk of therapy (basal, 0.79 +/- 0.09 ng/ml; 12 wk, 0.35 +/- 0.07 ng/ml). In marked contrast, all androgens fell significantly at each time period in response to surgical adrenalectomy, with an 81% maximum suppression of T, 73% of DHT, and 97% of delta 4-A. In response to estrogen suppression, plasma levels of FSH, LH, and prolactin did not change significantly throughout the treatment period in either therapy group. To examine possible contributions of the postmenopausal ovary to hormone levels during therapy, data from surgically castrate and spontaneously menopausal women were evaluated separately. No significant differences between the two groups were observed for E1, E2, T, DHT, DHEA-S, delta 4-A, LH, FSH, and prolactin. We conclude that equivalent and highly significant estrogen suppression occurs with either AG or surgical adrenalectomy although androgen secretion is preserved during AG treatment but not after surgical adrenalectomy. The combined effects of estrogen deprivation associated with androgen preservation might be significant in the therapeutic action of AG in hormone-responsive neoplasms.

Steroid hormone profiles in women treated with aminoglutethimide for metastatic carcinoma of the breast.

Recent evidence suggests that aminoglutethimide (AG), a known inhibitor of adrenal steroidogenesis, is a potent blocker of aromatase and thus of estrogen production. These properties of AG have been exploited clinically to reduce the biosynthesis of adrenal estrogen precursors and extraglandular estrogen production in postmenopausal women with metastatic breast carcinoma. In this study, we have explored the effects of AG on a variety of steroids, including delta 5-C19 and -C21 compounds and delta 4-C19 and -C21 steroids as well as plasma and urinary estrogens in a series of postmenopausal women with breast cancer treated for 2 to 26 weeks. Plasma concentrations of delta 5-C21 and -C19 compounds were reduced 3- to 5-fold during AG therapy and remained suppressed over the duration of the study. By contrast, the delta 4-steroids such as progesterone, androstenedione, and 17 alpha- hydroxyprogesterone rose 2- to 10-fold during the initial 2 weeks of AG treatment and then fell back to starting levels or were suppressed. Plasma levels of the potent androgens testosterone and dihydrotestosterone were relatively preserved during AG therapy. The possible contribution of the postmenopausal ovary to the above hormone levels during AG therapy was examined by comparing steroid values from surgically castrated and spontaneously menopausal women. No statistically significant differences between the two groups were observed. In response to AG therapy, plasma levels of estrone and estrone sulfate were decreased 61 to 72%, and urinary estrone similarly fell 85% over the 12-week period. Estradiol concentrations in urine and plasma were similarly reduced 40 to 66% from basal values over this same period.

In vivo and in vitro pharmacological studies of aminoglutethimide as an aromatase inhibitor.

Use of steroid biosynthesis inhibitors to suppress estrogen production is a logical strategy in the treatment of women with hormone-dependent breast cancer. The clinical availability of aminoglutethimide as an inhibitor of cytochrome P-450-mediated steroid hydroxylations prompted study of the precise pharmacological and biochemical effects of this drug. Pharmacokinetic studies revealed that aminoglutethimide alters its own metabolic clearance rate as well as that of dexamethasone, a synthetic glucocorticoid. The metabolic clearance rates of other steroids such as hydrocortisone, medroxyprogesterone acetate, and androstenedione, and estrone are not altered by aminoglutethimide. These findings led to development of a practical regimen of escalating aminoglutethimide dosage in combination with hydrocortisone for treatment of patients with breast carcinoma. Further studies focused upon the biochemical mechanism of estrogen suppression with aminoglutethimide. In vivo, isotopic kinetic data demonstrated that aminoglutethimide inhibits peripheral aromatase by 95 to 98% in postmenopausal women. In vitro experiments indicated that aminoglutethimide can effectively block aromatase directly in human breast tumors as well. With respect to relative potency, aminoglutethimide is a 10-fold more potent aromatase inhibitor than is testololactone but is less potent than are 4-hydroxyandrostenedione and several brominated androstenedione derivatives. Taken together, these studies suggest that aminoglutethimide blocks estrogen production at three sites in women with breast carcinoma: the adrenal cortex, extraglandular peripheral tissues containing aromatase, and breast carcinoma tissue itself.

Adequacy of estrogen suppression with aminoglutethimide and hydrocortisone as treatment of human breast cancer: correlation of hormonal data with clinical responses.

Human breast neoplasms can be divided into hormone-dependent and hormone-independent subtypes. Estrogen is the major hormonal stimulus for growth of the dependent tumors. Failure to respond to estrogen suppression therapy could reflect either an incomplete lowering of estrogens or the hormonal independence of the tumor. To address this issue, we compared the levels of several estrogens and other hormones in women experiencing objective responses (the responders) and disease progression (the progression group) during therapy with the aromatase-steroidogenesis inhibitor, aminoglutethimide, and replacement hydrocortisone. Pretreatment hormonal profiles of the estrogens, and androgens, ketosteroids, thyroxine, polypeptide hormones, and carcinoembryonic antigen did not differ significantly among response groups. During treatment, the levels of all estrogens were suppressed to a similar degree in the progression group and in the responders. Urinary estrone, for example, fell to 16.7 +/- 3.2% of basal in the responders versus 16.3 +/- 3.8% of basal in the progression group. These data suggested that lack of estrogen suppression did not explain the response to treatment in the patients receiving aminoglutethimide-hydrocortisone. This finding differs from our results in a similarly analyzed control group of patients treated with surgical adrenalectomy. Levels of the weak androgens, dehydroepiandrosterone sulfate and androstenedione, were found to be higher in the progression group compared to the responders. This observation could not be explained by differences in duration of treatment between groups. Analysis at 1 to 12 weeks, 13 to 24 weeks, and 25 to 36 weeks after initiating treatment indicated higher androgen levels at each time point in the progression group. In addition, the results were not attributable to differing serum levels of aminoglutethimide among responder groups. While the finding of higher androgen levels in the responder group remains unexplained, this study indicates that incomplete estrogen suppression is not responsible for lack of tumor response in patients with progressive disease during amino-glutethimide-hydrocortisone therapy.

Inhibition of pituitary-testicular function with [D-Trp6] luteinizing hormone-releasing hormone in rhesus monkeys.

The effect of [D-Trp6]LHRH, a potent agonist of LHRH, on pituitary-testicular responses was investigated in male rhesus monkeys. Acute administration of 5, 25, or 500 micrograms [D-Trp6]LHRH produced dose-related increases in serum testosterone and bioassayable LH levels. The administration of 500 micrograms [D-Trp6]LHRH twice weekly for 12 weeks led to a 75% decrease in the LH responses to successive doses of this peptide; testosterone responses in these animals were unchanged, however. The lack of any change in the motility or sperm number in semen obtained by electroejaculation suggested that there was no effect on spermatogenesis during the twice weekly administration. These animals were then treated with [D-Trp6]LHRH (500 micrograms daily) for 16 weeks. This caused dramatic decreases in the LH responses to the agonist in all four animals. The testosterone response was reduced in two and abolished in two animals. These latter two animals also lost their electroejaculatory response. During the recovery period following the cessation of treatment, these two animals produced ejaculates with no sperm, indicating that a transient period of azoospermia was achieved. The results of these studies suggest that 1) the responsiveness of the pituitary is more susceptible to desensitization by [D-Trp6]LHRH than that of the testes; and 2) even though chronic administration of [D-Trp6]LHRH suppressed the pituitary-Leydig cell axis in all monkeys, seminiferous tubular function was reduced only in those animals with very low androgen levels.

Adrenal suppression with aminoglutethimide. III. Comparison of plasma delta 4- and delta 5-steroids in postmenopausal women treated for breast carcinoma.

A regimen or aminoglutethimide in combination with replacement glucocorticoid has been used to suppress adrenal steroidogenesis in postmenopausal women with metastatic breast carcinoma. During acute and chronic treatment with aminoglutethimide, the levels of the delta 4-steroids [progesterone (P), 17 alpha-hydroxyprogesterone (17-delta 4-P), and androstenedione (delta 4-A)] and the delta 5-steroids [dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), and 17 alpha-hydroxypregnenolone (17-delta 5-P)] were determine. In the total group of women, the plasma levels of P and delta 4-A increased 2- to 3-fold (P less than 0.05) while 17-delta 4-P rose 10-fold (P less than 0.01) from basal concentrations of 0.65 +/- 0.07 to 6.48 +/- 1.46 ng/ml during the initial 2 weeks of therapy with aminoglutethimide (AG) and dexamethasone. These three steroids then fell to basal levels during chronic treatment (P and 17-delta 4-P) or were suppressed (delta 4-A; P less than 0.001). In contrast, the levels of delta 5-steroids (17-delta 5-P, DHEA, and DHEA-S) were reduced 3- to 5-fold during the initial 2 weeks of therapy and remained suppressed throughout. The relative levels of certain delta 5- and delta 4-steroids pairs were then examined. The ratio of 17-delta 5-P to 17-delta 4-P decreased from baseline values of 2.15 +/- 0.35 to 0.38 +/- 0.21 ng/ml (P less .02) with the initiation of therapy and remained low thereafter. A similar pattern for the ratios between DHEA and delta 4-A, and DHEA-S and delta 4-A was observed. This may indicate that the regimen of AG treatment utilized may facilitate the activity of the 3 beta-ol-dehydrogenase, delta 5- to delta 4-isomerase, and accelerate the conversion of delta 5- to delta 4-steroids. The patterns of suppression of the plasma delta 4- and delta 5-steroids in oophorectomized and spontaneously postmenopausal patients with intact ovaries were analyzed separately. The plasma levels of progesterone were higher during the first 2 weeks of therapy in surgically castrate women than in spontaneously postmenopausal women (0.72 +/- 0.25 vs. 0.47 +/- 0.20 ng/ml). A similar pattern was observed for 17-delta 4-P, DHEA, and DHEA-S indicating that the adrenals might contribute to this increase. In contrast, during chronic treatment the levels of all steroids were lower in surgically castrate women than in those with intact ovaries. This suggested residual ovarian steroid during AG administration.

Clinical usefulness of plasma androstanediol glucuronide measurements in women with idiopathic hirsutism.

Serum androstanediol glucuronide (3 alpha-diol G), a metabolite of the active androgens dihydrotestosterone and androstanediol, was elevated in 28 consecutive women with idiopathic hirsutism (IH). The mean 3 alpha-diol G level in the women with IH was 487 +/- 192 (+/- SD) ng/dL compared to 119 +/- 37 ng/dL in normal women (n = 50), and only 1 patient had a value overlapping with the normal range. Since 3 alpha-diol G appears to be formed entirely in target organs and has a long serum half-life, we studied its clinical usefulness by following women with IH during treatment. In 15 of 17 women with IH treated for 1-4 yr with glucocorticoids, contraceptives, or spironolactone, serum 3 alpha-diol G levels changed concordantly with clinical responses, in contrast to the poor concordance of serum testosterone (5 of 17), free testosterone (7 of 17), and androstenedione (7 of 17). Specifically, in IH patients treated with spironolactone, serum testosterone, free testosterone, and androstenedione levels changed little, yet clinical improvement frequently occurred, and this improvement was reflected by concomitantly lowered 3 alpha-diol G levels. Further, in 4 IH patients, discontinuation of effective therapy resulted in prompt increases in serum 3 alpha-diol G as harbingers of worsening hair growth. We, thus, conclude that serum 3 alpha-diol G measurements are clinically useful in evaluating hirsute women and correlate with the clinical responses to therapy.

Resistance of the ovary to blockade of aromatization with aminoglutethimide.

Aminoglutethimide (AG) is a potent inhibitor of aromatization in placental microsomes and in peripheral tissues in postmenopausal women. Aromatase inhibitors have been used to block estrogen production and induce breast tumor regression in rodents. To inhibit ovarian estrogen production, we administered various doses of AG and its highly potent D-stereoisomer to premenopausal women with breast carcinoma. However, at no dose level did AG consistently lower estrone and estradiol concentrations in plasma below those observed in normal menstruating women. Uniform increments in LH and FSH were also not observed. Only during the luteal phase were the levels of estradiol (but not estrone) significantly suppressed. These observations are best explained by the possibility that aromatase enzymes in the ovary, as opposed to those in the placenta and in peripheral tissues, are partially resistant to the effects of AG.

Cortisol and androgen secretion in a case of Nelson's syndrome with paratesticular tumors: response to cyproheptadine therapy.

Bilateral paratesticular tumors were observed in a 32-yr-old man 14 yr after he developed a pituitary tumor after adrenalectomy for Cushing's disease (Nelson's syndrome). Plasma ACTH concentrations were markedly elevated (mean, 6350 pg/ml), but urinary free cortisol concentrations were low (27-31 micrograms/24 h). Catheterization revealed a spermatic to peripheral venous gradient for cortisol consistent with secretion of this steroid by the tumor. This was confirmed by decreased cortisol excretion after tumor excision. Serum androgen (testosterone, androstenedione, dihydrotestosterone, and dehydroepiandrosterone-sulfate) and progestin (progesterone and 17-hydroxyprogesterone) concentrations were decreased and did not decline further after tumor removal. These latter observations suggested that the paratesticular tumors did not secrete appreciable testosterone or any of its immediate precursors. Serum gonadotropin levels were also low. Cyproheptadine treatment resulted in a marked lowering of plasma ACTH concentrations (221-320 pg/ml). This was associated with an increase in both plasma LH and testosterone concentrations. These observations are consistent with the hypothesis that ACTH may directly affect LH and testosterone secretion.

Response of the prepubertal ovary to acute chorionic gonadotropin administration: absence of modulation by growth hormone.

Twenty-five short term hCG stimulation tests were performed in seven prepubertal girls, aged 3-11 yr, who were being evaluated for short stature. Provocative testing revealed GH deficiency in all patients, but reevaluation of one girl at a later date showed normal somatotropin levels. The study protocol lasted 18 months and included testing before, during, and after 1 yr of GH therapy. Delta 4-Androstenedione, testosterone, estrone, and estradiol were determined 0, 24, 48, and 72 h after initiation of a two-injection course of CG. Significant responses (approximately 2-fold over baseline) to the stimulation tests occurred for all steroids except testosterone, though no augmented effects were found in the presence of human GH. The results indicate functional capability of the prepubertal ovary when exposed acutely to a LH-like material, but no role for somatotropin in gonadal steroid production in the prepubertal female.

Differential sex steroid negative feedback regulation of pulsatile follicle-stimulating hormone secretion in healthy older men: deconvolution analysis and steady-state sex-steroid hormone infusions in frequently sampled healthy older individuals.

The healthy aging male reproductive axis tends to exhibit a progressive decline in serum concentrations of biologically available testosterone with gradual concomitant reciprocal increases in both LH and FSH concentrations. However, relatively little is known about the sex steroid-mediated negative feedback regulation of physiologically pulsatile gonadotropin release in general, and episodic FSH release in particular, in older males. To examine the steroid hormone negative feedback control of pulsatile FSH secretion in healthy older men, we applied multiparameter deconvolution analysis to serum FSH (immunoradiometric assay) profiles obtained by sampling every 10 min over 24 h during steady state (4.5-day) infusions of estradiol (E2; 48 micrograms/day), 5 alpha-dihydrotestosterone (DHT; 7.0 mg/day), or 5% dextrose in water in five healthy older men, aged 60-73 yr. We observed the following principal responses: 1) both E2 and DHT significantly suppressed mean and 24-h integrated serum FSH concentrations (P < 0.032); 2) the calculated daily secretion rate of FSH fell significantly in all five individuals during DHT infusion; 3) the apparent half-life of FSH decreased during E2 (but not DHT) infusion; 4) DHT infusion reduced the mass and frequency of FSH secretory bursts significantly; 5) neither E2 nor DHT treatment significantly attenuated the release of FSH stimulated by consecutive iv injections of GnRH (10 and 100 micrograms); and 6) integrated 24-h serum LH (immunoradiometric assay) concentrations decreased significantly during both DHT and E2 infusions, whereas mean LH release after the serial GnRH injections was not altered. Compared to younger men studied earlier in an identical fashion, older men had significantly reduced FSH intersecretory burst intervals, reflecting a higher FSH pulse frequency at baseline and during the steroid infusions and a significantly lower mass of FSH secreted per burst during E2 infusion. We conclude that healthy older men maintain intact negative feedback responsiveness of the hypothalamo-pituitary gonadotroph unit to exogenously delivered sex steroid hormones, and that individual sex steroid hormones differentially regulate specific features of pulsatile FSH release and half-life in older men.

How effective is surgical adrenalectomy in lowering steroid hormone concentrations?

Surgical adrenalectomy produces objective tumour regression in 50-60% of estrogen receptor-positive women with metastatic breast carcinoma. Additional responses to antiestrogens or further suppression of estrogens with aminoglutethimide after adrenalectomy suggest the possibility of continued adrenal steroid secretion even after surgical ablation. The use of sensitive and specific RIAs allows precise determination of the degree of hormone suppression after adrenalectomy and could provide documentation of nonsuppression or escape from suppression in individual patients. To evaluate the possibility of continued hormone secretion, we measured 14 hormones in 26 postmenopausal women with breast carcinoma before and after adrenalectomy. While the mean levels of androgens were markedly suppressed [dehydroepiandrosterone sulfate (DHEA-S), 99%, androstenedione, 94%; testosterone, 77%; dihydrotestosterone, 73%] after adrenalectomy, estrogen concentrations fell to a much lesser extent (plasma estrone, 73%; urinary estrone, 86%; plasma estradiol, 53%; urinary estradiol, 67%). Examination of data in individual patients revealed incomplete suppression in several women (less than 50% suppression of plasma estradiol in 14 of 25 patients, of urinary estradiol in 4 of 22, and of urinary estrone in 1 of 22). Androgen concentrations also fell incompletely after adrenalectomy in a few patients. Androstenedione concentrations were greater than 2 SD above the group mean in 2 of 23 patients, and in 2 of 25 patients, DHEA-S concentrations were also greater that 2 SD above the group mean. Serial measurements of hormones over a 1- to 3-yr period following surgery revealed escape from suppression over time (i.e. greater than 2-fold increase in hormone levels) in 7 of 26 women. The practical significance of the lack of suppression or of escape from inhibition was assessed by comparing estrogen levels in responders vs. nonresponders to surgical adrenalectomy. Of all steroids measured, greater suppression of only 1 hormone (urinary estrone) was observed in responders vs. nonresponders. These data indicate that adrenalectomy does not uniformly suppress circulating androgen and estrogen levels in postmenopausal patients. Women who initially suppress after adrenalectomy may show recovery of either androgen or estrogen levels with time.

Acute effects of aminoglutethimide on testicular steroidogenesis in normal men.

Aminoglutethimide (AG), a known adrenal inhibitor, was administered acutely to normal men in order to study its effects on testicular steroidogenesis. Sixteen subjects between the ages of 21--30 yr received either placebo or 1250 mg AG in divided doses during a 24-h period. To reduce the contribution of adrenal steroids, adrenal function was inhibited in both groups of men by the administration of dexamethasone (2 mg) on the night of the experiment. As a result, mean morning plasma cortisol levels fell to less than 2 micrograms/100 ml. AG blunted the normal diurnal rise in testosterone, which was observed in men receiving placebo, and significantly suppressed the levels of this androgen at 0700 and 0900 h. Estradiol concentrations fell to a greater extent than those of testosterone. The differences between the placebo and drug treatment groups were significant at all time points except 1900 h. A pattern similar to that of estradiol was observed for plasma estrone. When the overall effect of AG administration was examined by analysis of variance, the differences in the levels of all three steroids produced by treatment were highly significant (P less than 0.01 to less than 0.001). After the inhibition of testosterone and estradiol levels, LH and FSH concentrations were significantly (P less than 0.01 and P less than 0.001, respectively) higher in men receiving AG than in those given placebo. However, the data exhibited a large variance due to pulsatile gonadotropin secretion. These observations suggested that AG induces an acute inhibition of testicular steroidogenesis and probably also of the aromatization of testosterone to estradiol.

Elevated production and metabolic clearance rates of androgens in morbidly obese women.

Blood production rates of testosterone, dihydrotestosterone (DHT), and 3 alpha-androstanediol (3 alpha-diol) were found to be approximately 2-fold elevated in morbidly obese, nonhirsute, normally menstruating women. Values were intermediate between those found in normal women and those in a group of nonobese normally menstruating women with idiopathic hirsutism. Elevated androgen production rates in obese women were associated with 2- to 3-fold increases in MCRs, presumably due to decreased levels of sex hormone-binding globulin. Thus, increased production rates were offset by increased MCRs, resulting in plasma testosterone, DHT, and 3 alpha-diol concentrations that were similar in the obese and normal women. By contrast, women with hirsutism had increased production rates associated with elevated plasma androgens as well as increased MCRs. Urinary excretion of testosterone glucuronide and 3 alpha-diol glucuronide (3 alpha-diol G) were elevated in both obese and hirsute women, paralleling the increased androgen production rates. Despite increased production rates and excretion of androgens, obese women exhibited no menstrual abnormalities, hirsutism, or other signs of virilism. To explore the apparent ineffectiveness of increased androgen production to produce virilizing symptoms, we measured plasma 3 alpha-diol G levels as a measure of peripheral androgen action. The mean +/- SE plasma 3 alpha-diol G was 53 +/- 8 ng/dl in obese women and 36 +/- 6 in normal women; by contrast, women with idiopathic hirsutism had levels of 440 +/- 99, a 12-fold elevation. Plasma testosterone glucuronide in obese and hirsute women were only 2- to 3-fold elevated, while plasma DHT glucuronide was not increased in obese women and was only 2-fold elevated in hirsute women. Thus, obesity is a state of increased androgen production and accelerated clearance. 3 alpha-diol G levels in obese women were only minimally elevated, in contrast to values in the hirsute women, perhaps reflecting the apparent androgen ineffectiveness.

Androgen-estrogen metabolism in women with upper body versus lower body obesity.

Androgen and estrogen production rates were examined in 29 morbidly obese women with upper or lower body obesity. Although blood production rates of testosterone (T), dihydrotestosterone, and androstenedione (A4) were elevated in all of these women, those with upper body obesity (waist-height ratios, greater than 0.85) had higher T and production rates than women with lower body obesity (waist-height ratio less than 0.75). A4 was equally elevated in women with upper and lower body obesity. Peripheral aromatization of A4 to estrone (E1) averaged 1.67% in women with upper body obesity, but was elevated at 2.54% in women with lower body obesity. Urinary E1 production rates averaged 466 +/- 295 nmol/day (172 +/- 109 micrograms/day) in women with upper body obesity. Thus, women with lower body obesity had higher E1 production rates due entirely to increased peripheral aromatization. Women with upper body obesity were observed to have higher serum T and estradiol (E2) levels than women with lower body obesity. Further, upper body obesity was associated with decreased levels of sex hormone-binding globulin (16.1 +/- 5.7 nmol/L vs. 18.9 +/- 6.1 in women with lower body obesity). As a result, free T levels averaged 98.8 +/- 39.2 pmol/L in women with upper body obesity vs. 82.2 +/- 33 in women with lower body obesity. Similarly, serum free E2 levels were higher in women with upper body vs. lower body obesity. The data demonstrate that sex hormone production and metabolism are different in morbidly obese women with these differing phenotypes. Women with upper body obesity have higher androgen production rates and higher free T and free E2 levels, whereas women with lower body obesity make increased amounts of E1 from peripheral aromatization. The biological significance of increased aromatization may be offset by increased free E2 levels in women with upper body obesity.

Prolonged negative feedback suppression after estradiol administration: proposed mechanism of eugonadal secondary amenorrhea.

The finding of normal gonadotropin and estradiol levels in eugonadal women with secondary amenorrhea suggests a disordered feedback relationship of the hypothalamic-pituitary-ovarian axis. To identify possible defects in negative and positive feedback, we compared the effects of five daily injections of 17 beta-estradiol (E2) in 13 normal women and 11 eugonadal patients with absent cyclic menses. The suppression phase of negative feedback was normal, as LH and FSH were similarly lowered in both groups on day 3. Continued LH (P less than 0.01) and FSH (P less than 0.02) inhibition on day 10 of the protocol, 5 days after the last E2 injection, indicated a defect in the recovery phase of negative feedback in the 11 amenorrheic women. In the 4 patients studied gonadotropin suppression persisted for 3 weeks, E2 did not blunt pituitary responsiveness to GnRH in the amenorrheic women, suggesting a central nervous system site for prolonged gonadotropin inhibition. Nine normal but only 2 amenorrheic women X2 = 4.15; P less than 0.05) exhibited a positive feedback increase in LH on days 4-6. We propose that a defect in the recovery phase of negative feedback to E2 rather than absent positive feedback may be the dominant physiological abnormality which causes secondary amenorrhea by preventing early follicular phase gonadotropin increments and follicular maturation.

Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men.

Serum GH concentrations are increased in fasted or malnourished human subjects. We investigated the dynamic mechanisms underlying this phenomenon in nine normal men by analyzing serum GH concentrations measured in blood obtained at 5-min intervals over 24 h on a control (fed) day and on the second day of a fast with a multiple-parameter deconvolution method to simultaneously resolve endogenous GH secretory and clearance rates. Two days of fasting induced a 5-fold increase in the 24-h endogenous GH production rate [78 +/- 12 vs. 371 +/- 57 micrograms/Lv (Lv, liter of distribution volume) or 0.24 +/- 0.038 vs. 1.1 +/- 0.16 mg/m2 (assuming a distribution volume of 7.9% body weight), P = 0.0001]. This enhanced GH production rate was accounted for by 2-fold increases in the number of GH secretory bursts per 24 h (14 +/- 2.3 vs. 32 +/- 2.4, P = 0.0006) and the mass of GH secreted per burst (6.3 +/- 1.2 vs. 11 +/- 1.6 micrograms/Lv, P = 0.002). The latter was a result of increased secretory-event amplitudes (maximal rates of GH release attained within a burst) with unchanged secretory burst durations. GH was secreted in complex volleys composed of multiple discrete secretory bursts. These secretory volleys were separated by shorter intervals of secretory quiescence in the fasted than fed state (respectively, 88 +/- 4.2 vs. 143 +/- 14 min, P = 0.0001). Similarly, within volleys of GH release, constituent individual secretory bursts occurred more frequently during the fast [every 33 +/- 0.64 (fasted) vs. every 44 +/- 2.0 min (fed), P = 0.0001]. The t1/2 of endogenous GH was not significantly altered by fasting [18 +/- 2.2 (fasted) vs. 20 +/- 1.5 min (fed), P = 0.47]. Serum insulin-like growth factor I concentrations were unchanged after 56 h of fasting. In conclusion, the present data suggest that starvation-induced enhancement of GH secretion is mediated by an increased frequency of GHRH release, and longer and more pronounced periods of somatostatin withdrawal.

Short-term modulation of the androgen milieu alters pulsatile, but not exercise- or growth hormone (GH)-releasing hormone-stimulated GH secretion in healthy men: impact of gonadal steroid and GH secretory changes on metabolic outcomes.

Gonadal steroids are known to alter GH secretion as well as tissue metabolism. The present study was designed to examine the effects of short term (2- to 3-week) alterations in gonadal steroids on basal pulsatile (nonstimulated) and exercise- and GH-releasing hormone-stimulated GH secretion, urinary nitrogen excretion, and basal and exercise-stimulated oxygen consumption. Two protocols were conducted, which reflect a total of 18 separate studies. In the first paradigm, 5 healthy young men were each studied in a double blind, randomized manner during 3 different gonadal hormone manipulations, in which serum testosterone was varied from hypogonadal (induced by leuprolide) to eugonadal (saline injections) to high levels (testosterone enanthate, 3 mg/kg.week, i.m.). There was a washout period of 8 weeks between treatments. In the second protocol, 3 of the original subjects were studied after 2 weeks of treatment with stanozolol (0.1 mg/kg.day). Two to 3 weeks after the desired changes in serum testosterone, each subject was admitted to the General Clinical Research Center for study. The hypogonadal state (serum testosterone, 33 ng/dL) increased urinary nitrogen loss (by 34%; P < 0.005) and decreased basal metabolic rate (by 12%; P < 0.02) compared with the eugonadal state (testosterone, 796 ng/dL). High dose testosterone (1609 ng/dL) further decreased urinary nitrogen loss over the eugonadal state (by 16%; P < 0.05). Stanozolol yielded the lowest urinary nitrogen excretion of all (P < 0.03). Like urinary nitrogen, the basal metabolic rate showed the greatest change between the hypogonadal and eugonadal states (12%; P < 0.02), with a lesser change during high dose testosterone treatment (4%). Analogously, end-exercise oxygen consumption rose by 11% between the hypogonadal and eugonadal states (P < 0.05). Between the hypogonadal and eugonadal states, no significant changes in pulsatile (nonstimulated), exercise-stimulated, or GRF-stimulated GH secretion or serum insulin-like growth factor I concentrations were observed. Raising testosterone to supraphysiological levels increased pulsatile GH secretion by 62% over that with leuprolide and by 22% over that with saline (P < 0.05). High dose testosterone treatment also increased serum insulin-like growth factor I concentrations by 21% and 34% over those during the eugonadal and hypogonadal states, respectively (P < 0.01). Testosterone did not affect either exercise- or GRF-stimulated GH secretion. In protocol 2, stanozolol did not affect any parameter of GH secretion. To examine the interaction between GH secretion and testosterone on urinary nitrogen excretion and basal metabolic rate, a one-way analysis of covariance was undertaken. Statistical examination of GH production as the covariate and testosterone (by tertile) as the interactive factor demonstrated significant relationships between serum testosterone levels and either urinary nitrogen (P < 0.02) or basal metabolic rate (P < 0.01), but not GH secretion (P = NS). In summary, these results demonstrate that short term modulation of the androgen milieu affects metabolic outcome without necessitating changes in GH secretion. These results have significance for both normal physiology and for the treatment of hypogonadal GH-deficient patients.

Alterations in pulsatile luteinizing hormone and follicle-stimulating hormone secretion in idiopathic oligoasthenospermic men: assessment by deconvolution analysis--a clinical research center study.

To investigate the nature of neuroendocrine disturbances of the hypothalamo-pituitary-gonadal axis in idiopathic male infertility, we studied 14 infertile men with oligoasthenozoospermia (OLIGO) and 15 age-, body mass index-, and community-matched euspermic controls by blood withdrawal at 10-min intervals for 12 h to encompass basal (8-h) and exogenous GnRH-stimulated (4-h) pulsatile release of LH and FSH (by immunoradiometric assay) as well as testosterone (by RIA). Deconvolution analysis was used to estimate endogenous LH and FSH half-lives, secretory burst frequency, amplitude, duration, and mass. OLIGO men exhibited normal serum concentrations of total, free, and percent dialyzable testosterone and estradiol, but distinct dynamic alterations within the LH and FSH axes; namely (P < 0.05), 1) a prolonged half-life of LH (OLIGO, 95 +/- 19 min; control, 80 +/- 9.3 min) and a reduced half-life of FSH (OLIGO, 260 +/- 79 min; control, 320 +/- 93 min); 2) a low LH, but normal FSH, secretory burst frequency (OLIGO, 12 +/- 3.4; control, 15 +/- 3.0 LH pulses/day); 3) a decreased serum testosterone peak frequency (OLIGO, 16 +/- 4.3; control, 21 +/- 3.2 peaks/day); and 4) an amplified mass of LH (1.1- to 1.3-fold higher in OLIGO) and FSH (2.4- to 2.7-fold higher in OLIGO) secreted per burst basally as well as after GnRH injection. These disturbances were readily distinguishable from the neuroendocrine dysregulation described in other states of male hypogonadotropism (e.g. uremia, fasting, and aging).