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At least 685 records · Page 38Linked to original sources
PubMed1994

Reciprocal changes in plasma corticosterone and testosterone in stressed male rats maintained in a visible burrow system: evidence for a mediating role of testicular 11 beta-hydroxysteroid dehydrogenase.

The purpose of these studies was to investigate the possible role of rat Leydig cell 11 beta-hydroxysteroid dehydrogenase (11HSD) in mediating the inhibitory effects of corticosterone on testosterone production. In a unique communal environment, the visible burrow system, male Long-Evans rats spontaneously segregated into unstressed dominant and stressed subordinate social relationships. Subordinate animals had elevated plasma corticosterone and diminished circulating testosterone levels relative to the dominant animals. The categories of animals were distinguished by behavioral criteria: weight change, wounds received, offensive and defensive behavior, and freedom of movement. As a result of their persistently elevated corticosterone levels, subordinate animals had smaller thymi and larger adrenals and spleens than dominants. We have postulated that Leydig cells are protected against the inhibitory effects of glucocorticoids on testosterone secretion by the inactivating effects of 11HSD. High corticosterone and low 11HSD are predicted to suppress testosterone production, and normal or diminished corticosterone levels combined with normal or elevated 11HSD should permit undiminished testosterone production. Consistent with these predictions, the testes of subordinate animals contained significantly lower 11HSD activity than those of dominant animals. The 11HSD of livers of subordinate and dominant animals were statistically indistinguishable. The results of this study support the postulated role of 11HSD as a protector of Leydig cell function.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1994

Testosterone productivity and histostructural changes of autotransplanted rat Leydig cells.

To investigate the possibility of in vivo transplantation of Leydig cells as a new biologic androgen replacement therapy, the Leydig cells procured from 6 week-old male Sprague-Dawley rats were autotransplanted, and the level of testosterone secretion and histostructural changes were observed. The renal subcapsular and intraperitoneal transplant showed higher levels of testosterone compared to subcutaneous or scrotal counterparts, and the number of transplanted cells was correlated with the level of measured testosterone. Furthermore, if the Leydig cells were transplanted intraperitoneally after the uptake on synthetic collagen, testosterone levels were higher than the ones simply transplanted without synthetic collagen uptake, resulting in 27 fold increase at 3 months. The activity of 125I-hCG decreased 20 to 40% at each month after transplantation compared to the normal levels, but no statistical significance was noted among different periods. The histologic examination revealed neovascularized capillaries and well demarcated sheet-like group of eosinophilic Leydig cells were observed at 4 weeks. But the evidence of destructive changes such as a focal inflammation with central dystropic ossification could be noted after 3 month. On electron microscopy, the marked indentation of nucleus and presence of lipochrome pigment were seen, and the number and size of smooth endoplasmic reticulum and mitochondria were reduced after 3 month. In conclusion, testosterone output could be increased to the physiologic range by increasing the number of transplant cells or utilizing collagen uptake but further effort is necessary on delaying or preventing the structural and functional decrement of Leydig cells.

Animals↗
PubMed2003

Virilization in bilateral macronodular adrenal hyperplasia controlled by luteinizing hormone.

We report a case of a virilized 59-yr-old woman with elevated serum testosterone levels and bilateral macronodular adrenal hyperplasia. The patient underwent laparoscopic right adrenalectomy, after which the elevated testosterone level transiently normalized. The immediate postoperative depression of the testosterone level suggested that the process was driven by gonadotropins that were suppressed by the stress of surgery. The excised right adrenal mass contained testosterone by immunohistochemistry and LH receptor mRNA by in situ hybridization. The recurrence of hyperandrogenemia suggested that the enlarged left adrenal was also secreting testosterone. The serum testosterone level increased in response to im injection of human chorionic gonadotropin, suggesting control by aberrant LH receptors. Injection of leuprolide acetate (7.5 mg im) to suppress LH levels resulted in normalization of the testosterone level 12 d later that persisted for several weeks. Ectopic receptors mediating Cushing's syndrome have been described in several cases of bilateral adrenal hyperplasia and adrenal adenoma. This is the first case to our knowledge in which pure androgen overproduction in adrenal hyperplasia has been shown to be controlled by LH receptors. In our patient, the control of androgen secretion by LH may explain the postmenopausal onset of virilization and the transient postoperative normalization of the serum testosterone level.

Adrenal Gland Diseases↗
PubMed1999

Disruption of the young-adult synchrony between luteinizing hormone release and oscillations in follicle-stimulating hormone, prolactin, and nocturnal penile tumescence (NPT) in healthy older men.

The healthy human male hypothalamo-pituitary-gonadal axis exhibits age-dependent loss of coordinate LH-testosterone secretion. A putative independent defect in Leydig-cell steroidogenesis with aging would confound the attribution of such LH-testosterone asynchrony to a hypothalamo-pituitary locus per se. Accordingly, here we appraise by sampling every 2.5 min overnight the joint synchrony of moment-to-moment LH release with simultaneously monitored pituitary FSH secretion, prolactin release, and nocturnal penile tumescence (NPT) oscillations, as a neurophysiological correlate of sleep regulation) in 10 young (ages 21-34) and 8 older (ages 62-72) healthy men. Joint synchrony for paired LH-FSH, LH-prolactin, and LH-NPT observations in young vs. older individuals was quantified by the cross-approximate entropy (cross-ApEn) statistic, with larger cross-ApEn values indicating greater two-variable asynchrony. Concomitantly, we assessed (possible) univariate changes with age for each of LH, FSH, prolactin, and NPT, as quantified by approximate entropy (ApEn). Hormone assays were performed by random-access direct chemiluminescence analyzer. Overnight mean (+/- SEM) serum LH concentrations (IU/L) were equivalent in older (3.1 +/- 0.31 IU/L) and younger (2.9 +/- 0.29) men, as were their serum total testosterone concentrations; viz., 425 +/- 48 (older) and 523 +/- 40 (younger) ng/dL. However, all three sets of paired time-series were significantly more asynchronous in the older cohort. First, cross-ApEn of paired LH-FSH release was significantly higher (or more asynchronous) in older subjects; viz., 1.902 +/- 0.022 in older men vs. 1.607 +/- 0.058 in younger individuals (P = 0.0005). Second, cross-ApEn of paired LH and prolactin release was 1.744 +/- 0.085 in older volunteers vs. 1.346 +/- 0.084 in younger subjects (P = 0.0046). Third, and most notably, cross-ApEn for the joint LH-NPT observation time-series was significantly greater in older subjects at 1.771 +/- 0.056 vs. 1.223 +/- 0.086 (young) (P = 0.0001), thereby denoting loss of coordination between (neural) signals directing intermittent LH secretion and those governing sleep-associated penile tumescence in older men. Among one-variable results, only ApEn of LH release was significantly higher in older individuals at 1.323 +/- 0.058 vs. 0.897 +/- 0.089 in younger subjects (P = 0.0019), signifying greater disorderliness of the LH secretory process in aged men. Individual ApEn values of FSH and prolactin release and NPT were age-invariant. In ensemble, the present clinical experiments indicate that, within the aging male reproductive axis, bihormonal network disruption is more pronounced than individual signal disruption. We suggest that abrogation of joint synchrony among hypothalamically directed pituitary hormones and a neurogenically organized sexual response (nocturnal penile tumescence) can be unified thematically under an hypothesis of disrupted central nervous system hypothalamo-pituitary network coordination in human aging. Such implicit disarray of multinodal communication is of consequence both scientifically and clinically, especially in proposing aging theories and intervention strategies.

Adult↗
PubMed1982

Effects of cranial cervical ganglionectomy and castration of male lambs. III. Hormonal responses following administration to gonadotrophin releasing hormone (GnRH).

Entire and castrate male lambs, which were cranial cervical ganglionectomized (GX) or untreated, were utilized in a study of responses to intravenous GnRH; 24 animals were treated at both 101 and 277 days of age. GX caused a reduction in basal LH concentrations of both wethers and rams at the first sampling, but increased pre-injection levels of this hormone in 277 day old wethers. Basal LH levels of castrates were substantially higher than those of entires, but GX had no significant influence on pretreatment testosterone secretion in rams. GnRH treatment elevated plasma LH levels in all animals, while in entires increases in testosterone concentrations also occurred. Castration significantly increased peak LH levels together with total LH output. At neither age were the LH or testosterone reponses influenced significantly by GX, nor was the interaction of castration and GX significant for LH response data. The major effect of age at GnRH treatment was that markedly higher testosterone responses were recorded from the older rams.

Journal Article↗
PubMed1991

Social control of reproduction in breeding and non-breeding male naked mole-rats (Heterocephalus glaber).

Eight male naked mole-rats, from three colonies were studied in captivity. When non-breeding male naked mole-rats were removed from their colonies and paired with a non-breeding female, or removed and housed singly for 6 weeks before pairing with a female, concentrations of urinary testosterone and plasma luteinizing hormone (LH) increased significantly (P less than 0.05). Concentration of these hormones were highest while the males were singly housed: urinary testosterone (mean +/- s.e.m.) increased from 8.2 +/- 1.3 ng/mg urinary creatinine (Cr) in a non-breeder in a colony to 49.1 +/- 5.5 ng/mg Cr when singly housed and 21.8 +/- 2.5 ng/mg Cr when paired with a female. Plasma LH concentrations increased from 4.7 +/- 1.0 miu/ml when a non-breeder in a colony to 19.8 +/- 4.0 miu/ml when singly housed and 9.9 +/- 1.1 miu/ml when paired with a female. After pairing with a female, the pattern of urinary testosterone secretion in the male was synchronized with the ovarian cycle of the female mate, such that urinary testosterone concentrations were significantly higher during the early follicular phase of the female's cycle (P less than 0.05). These results suggest that active suppression of reproductive physiology by social cues occurs in non-breeding male naked mole-rats, and that this is readily reversible if social cues are removed and males are housed singly. When a male was subsequently paired with a female, endocrine suppression was partially reimposed on the reproductively active males, such that urinary testosterone concentrations were suppressed to values similar to those in non-breeding males, except for periods prior to mating.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Comparison of the effects on purified Leydig cells of four hormones (oxytocin, vasopressin, opiates and LHRH) with suggested paracrine roles in the testis.

Four hormones have been identified by various authors as possible paracrine regulators of testicular Leydig cells. The aim of this study was to evaluate their effects on purified adult rat Leydig cells under various conditions in vitro, and then to assess whether comparable effects occurred in vivo. In agreement with previous findings, an LHRH agonist (LHRH-A) exerted clear-cut effects on testosterone secretion by Leydig cells both in vitro and in vivo. On its own, LHRH-A stimulated testosterone production by Leydig cells for up to 24 h in culture but inhibited testosterone production stimulated by human chorionic gonadotrophin (hCG) between 24 and 72 h of culture. In-vivo, unilateral intratesticular injection of adult rats with 1 ng LHRH-A resulted 5 h later in a significant increase in testosterone concentrations in testicular interstitial fluid (IF). Vasopressin exerted effects in vitro which were similar to those of LHRH-A. On its own, vasopressin stimulated testosterone production for up to 5 h of culture, but not thereafter, while in the presence of hCG, vasopressin inhibited testosterone production beyond 24 h of culture. The initial stimulatory effect of vasopressin on testosterone production occurred with concentrations of 1 nmol/l and higher, but the magnitude of stimulation (threefold or less) was considerably less than that induced by LHRH-A (ninefold) over the same time period. In contrast to LHRH-A, unilateral intratesticular injection of vasopressin in high doses (20 and 2 ng) had no effect on IF testosterone levels 5 h later.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Direct and indirect effects of murine interleukin-2, gamma interferon, and tumor necrosis factor on testosterone synthesis in mouse Leydig cells.

It was recently observed that treatment of patients with a high dosage of human interleukin (IL-2) resulted in suppression of plasma concentrations of testosterone. A murine model was developed to assess the direct and indirect effects of murine IL-2 and the secondarily released cytokines, gamma interferon (INF gamma), and tumor necrosis factor (TNF alpha), on testosterone production in isolated Leydig cells. Pretreatment for 24 hours with IL-2 (100 to 500 IU/ml) or INF gamma (100 to 1000 IU/ml) significantly decreased testosterone production in response to luteinizing hormone (LH; P < 0.02 and 0.005, respectively). The combinations of INF gamma with either TNF alpha or IL-2 produced enhanced suppressive effects on Leydig cell testosterone production. Steroidogenic precursors (22-hydroxycholesterol, 17 alpha-hydroxypregnenolone, and dehydroepiandrosterone) restored testosterone secretion to control levels after preincubation with INF gamma or TNF alpha. In contrast, the inhibition of testosterone synthesis produced by either IL-2 or INF gamma plus TNF alpha could be reversed by 17 alpha-hydroxypregnenolone and dehydroepiandrosterone, but not by 22-hydroxycholesterol (P < 0.01). Dibutyryl cyclic adenosine monophosphate was also ineffective in reversing the inhibitory effects of these cytokines on synthesis. Although IL-2 directly inhibited synthesis in isolated Leydig cells, it stimulated testosterone production (P < 0.005) in minced murine testes. This suggests that IL-2 releases regulatory factors from other cells that were able to overcome the direct inhibitory effect of IL-2. This stimulatory effect was not caused by INF gamma and TNF alpha because INF gamma alone or with TNF alpha inhibited (P < 0.005) testosterone production in minced testes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Male infertility with chromosomal abnormalities. I. XYY syndrome].

Chromosomal abnormalities are found in a considerably high percentage of cases of male infertility, in particular azoospermia. We report a case of the XYY syndrome and review the literature. A 36-year-old man, a factory hand, presented with infertility. He was safely delivered at term as a fourth child when his father was 41 years old and his mother 38. He had no delinquent or criminal record. His height was 179 cm, weight 75 kg and distance of extended hands 184 cm. No gynecomastia was noticed. Both testes were 8ml in size and growth of pubic hair and penis were normal. Severe oligozoospermia was identified in semen analysis. Seminal vesiculography showed pathological dilatation of the seminal vas end. The testicular biopsy specimens revealed spermatogenic arrest for the most part. Chromosomal analysis showed 47, XYY karyotype; and, two Y-chromatin was revealed in cultured lymphocytes. Though plasma gonadotropin levels were high, testosterone, estradiol, prolactin, TSH, GH, T3 and T4 levels were within normal limits. Pituitary reserve function for secreting gonadotropins and Leydig cell reserve function to secrete testosterone have been found to be almost normal.

Adult↗
PubMedDate not supplied

[Secretion of biologically active and immunoreactive luteinizing hormone in patients with polycystic ovary syndrome].

Basal secretion of immunoreactive and bioactive LH was measured in 24 patients with polycystic ovaries, secretion during LH-RF test in 18 patients. Basal LH level was assessed from in vitro testosterone secretion by murine Leydig's cells. The content of basal LH and basal LH to FSH ratio in patients with the polycystic ovaries syndrome was markedly increased vs. the norm. Three types of gonadotroph responses were observed in the patients in response to LH-RF, these responses differing by increment rate, time course of secretion, and ratio of secreted basal and immunoreactive LH. Gonadotroph response was found related to ovarian morphology and clinical manifestations of the disease. Administration of LH-RF to patients with polycystic ovaries and tecomatosis changed the ratio of secreted basal and immunoreactive LH by reducing basal LH level. In young girls and women aged under 20 the increment of basal and immunoreactive LH noticeably surpassed its values in older patients with longer disease duration.

Adolescent↗
PubMedDate not supplied

Inhibition of gonadotropin and prostaglandin stimulation of testicular steroidogenesis in malnourished rats.

The effect of human chorionic gonadotropin (hCG) and prostaglandin E1 (PGE1) on testicular steroidogenesis in protein-deficient and refed rats was studied in vitro. The malnourished, refed, and control rats were found to secret testosterone in response to hCG and PGE1 stimulation. There was a significant reduction in the basal level of secretion in the malnourished rat testis (1.0 +/- 0.4 nMol/3 hr./Testis). Malnourished rats refed with adequate protein diet responded to hCG and PGE1 stimulation in a similar manner to normally-fed adult rats.

Alprostadil↗
PubMed1991

Embryonic sex hormones in birds.

Hormone activity of embryonic gonads in birds was demonstrated by grafting and culture experiments. Anti-Müllerian hormone responsible for the regression of the Müllerian ducts in the male is most probably a glycoprotein. Whether the testis also secretes testosterone has long been disputed, but most arguments are against this possibility. From early stages of development, the ovary secretes estrome and estradiol. However, it could not be demonstrated unambiguously whether estrogen is identical with the sex inducing substance in the female. The hypophysis seems to control ovarian estrogen secretion at 10-13 days of incubation in the chick embryo.

Animals↗
PubMed1984

[Excessive gynecomastia in boys. Effective medical treatment using danazol (Winobanin)].

The purpose of this study was to provide a medical alternative to mastectomy in boys with excessive breast development. Eleven boys with bilateral gynecomastia, ranging in size between 9 X 7 cm and 3 X 3 cm in diameter, were treated with 200 mg of Danazol daily for 6 months. This therapy led to a reduction in breast size between 3 X 3 cm and 1,5 X 1,5 cm. The antigonadotropic action of Danazol was documented by inhibition of basal gonadotropin secretion, by disappearance of normal sleep dependent rhythms and by a reduced pituitary response to stimulation. Simultaneously, plasma testosteron secretion was suppressed without reduction of testicular volumes. In all patients the hypothalamo-pituitary gonadal axis normalized within 67 months after termination of therapy and no relapse was observed over a control period up to 26 months. The continuing regression after Danazol treatment emphasizes the effectiveness of drug therapy as an alternative regimen to surgical intervention.

Adolescent↗
PubMed1991

Pattern of secretion of bioactive and immunoreactive gonadotrophins in normal pubertal children.

OBJECTIVE: The aim was to investigate the relationship between the nocturnal pulsatile secretory patterns of immunoreactive and bioactive luteinizing hormone in normal children at various stages of puberty. DESIGN: Blood samples were taken at 15-minute intervals from 2000 hours to 0800 hours. Pubertal stage was assessed by the method of Tanner (1962). PATIENTS: Thirty-four healthy siblings (17 males, 17 females) of diabetic children were recruited (median age 13.1, range 9.1-20.9 years). They were of normal height, non-obese, and covered the range of puberty. MEASUREMENTS: Follicle stimulating and luteinizing hormone levels were measured by radioimmunoassay in all 34 subjects; bioactive LH (B-LH) was assayed in a subgroup of 13 subjects selected to encompass the range of normal puberty. Oestradiol (girls) and testosterone (boys) were also measured at hourly intervals. RESULTS: Immunoreactive luteinizing and follicle stimulating hormone concentrations showed a progressive rise during puberty in both sexes. FSH concentrations were significantly higher in females than in males at all stages of puberty. Overnight mean bioactive luteinizing hormone concentrations were higher than immunoreactive luteinizing hormone levels in all the girls studied (n = 7). Although the number of bioactive luteinizing hormone pulses (31) was greater than immunoreactive pulses (27), the profiles were generally very similar. In the early pubertal girls an increase in the bioactive: immunoreactive ratio was observed during the middle of the night with the onset of pulsatility. Oestrogen was detected in the girls in breast stage 4-5 but not in two of the early pubertal girls, despite pulses of immunoreactive and bioactive luteinizing hormone. The boys had higher mean bioactive than immunoreactive luteinizing hormone levels and overall bioactive and immunoreactive luteinizing hormone and testosterone concentrations increased with puberty stage. Concordance between bioactive and immunoreactive hormone pulses was good although more immunoreactive pulses (16) were seen than bioactive pulses (14). As in the girls, an increase in the bioactive: immunoreactive ratio was observed in the middle of the night with the onset of pulsatility at genital stage 2 but, in contrast to the oestrogen data in the girls, testosterone secretion always followed luteinizing hormone pulsatility overnight. CONCLUSION: We conclude that mean overnight immunoreactive luteinizing and follicle stimulating hormone concentrations increase during puberty in both sexes. Bioactive luteinizing hormone levels are two to three times higher than immunoreactive luteinizing hormone in both sexes, but there is very little discordance between immunoreactive and bioactive luteinizing hormone pulsatility. The bioactive: immunoreactive ratio increases with the occurrence of pulsatility overnight in early pubertal children. The relationship between these changes in bioactive and immunoreactive luteinizing hormone and sex steroids is clearest in boys where the nocturnal testosterone rise always follows pulsatile LH secretion.

Adolescent↗
PubMed1989

Absence of direct effects of GnRH on testicular steroid secretion in the ram.

Effects of GnRH, administered via the testicular artery, on testicular steroidogenesis were studied in rams during the non-breeding season. Concentrations of testosterone and 17-hydroxyprogesterone in testicular venous blood showed similar profiles which were identical for GnRH-treated (0.5 ng infused over 60 min or 25 ng injected) and control testes. Increases of testicular venous concentration of both hormones were only marginally reflected in peripheral venous concentrations. Peripheral administration of hCG (200 i.u., i.v.) stimulated testosterone secretion to a larger extent than 17-hydroxyprogesterone secretion in 10/11 rams, GnRH-treated and control testes showing identical responses. High testicular venous concentrations of both hormones after administration of GnRH were paralleled by increased concentrations of endogenous LH. These LH peaks were evoked by 25 ng GnRH in 7/8 rams. The observed effects of GnRH treatment on testicular steroid secretion thus cannot be considered to be the result of direct stimulation of steroidogenesis by GnRH.

Animals↗
PubMed2003

Transdermal testosterone delivery: testosterone patch and gel.

Testosterone replacement treatment is usually life-long. Fortunately, testosterone administration is relatively safe and until the age of 50 years few side effects are noted with normal doses of testosterone. After the age of 50 years when prostate disease becomes more prevalent, shorter-acting testosterone preparations, allowing a fast reduction of circulating testosterone levels, may be an advantage. Testosterone has an impact on sexual and non-sexual behaviour and short-acting testosterone preparations may be better suited for the initiation of long-term administration allowing the monitoring of behavioural effects. Testosterone can be delivered to the circulation through the intact skin, both genital and non-genital. Transdermal administration delivers testosterone at a controlled rate into the systemic circulation, avoiding hepatic first pass and reproducing the diurnal rhythm of testosterone secretion and without the peak and trough levels observed with the use of the traditional long-acting testosterone injections. In conclusion, both the testosterone patch and testosterone gel are valuable contributions to androgen replacement treatment meeting the requirements specified for testosterone replacement treatment.

Administration, Cutaneous↗
PubMed1982

Serum Testosterone response to single injection of hCG ovine-LH and LHRH in male rats.

A biphasic pattern of testosterone secretion in response to a single injection of 100 IU hCG has been observed in the rat. Serum testosterone increased from basal levels of 8.7 +/- 3.1 ng/ml (mean +/- SEM) to 23.0 +/- 1.4 ng/ml within 2 h of hCG-stimulation and returned to control levels by 2 days. A second, delayed, but significant increase in serum testosterone occurred, reaching a peak of 24.6 +/- 4.0 ng/ml at 3 days and declining to basal values at 5 days. To study this response further, lower doses of hCG were tried. Administration of 10 IU hCG produced a single peak of testosterone, which did not occur until 24 h. Differences in the serum testosterone response were related to the concentration of hCG measured in the serum after injection, as injection of 1 IU, which failed to increase serum hCG levels above detection, was also inadequate to increase serum testosterone. The response after stimulation with 500 micrograms ovine-LH or 0.1-10.0 micrograms LHRH was also evaluated. Injection of 500 micrograms ovine-LH produced a significant rise in serum testosterone reaching a peak at 2 h of 25.2 +/- 2.6 ng/ml and subsequently declining over the next 48 h to control levels where it remained for 5 days. Stimulation with doses of 0.1 - 10.0 micrograms LHRH produced rapid and short increase in serum LH concentration which induced peaks of testosterone up to 48.8 +/- 14.1 ng/ml 1 h post injection. No secondary peak of testosterone followed. Failure of ovine-LH and LHRH to produce a second testosterone peak suggests that this response may be due to a re-stimulation of the Leydig cell by elevated levels of hCG which persist until the fourth day after injection.

Animals↗
PubMed1976

Clinical and laboratory heterogeneity in idiopathic hypogonadotropic hypogonadism.

Six young men with idiopathic hypogonadotropic hypogonadism had 24-h frequent blood sampling studies for measurement of LH, FSH and testosterone. Five of the patients had LH and FSH measured after administration of 100 mug LH-RH during waking and then during sleep. Four of the patients had testicular biopsies performed. The results of the present studies showed that 4 of the patients had no evidence of episodic LH, FSH, or testosterone secretion. The two patients who showed significant sleep related pulses of LH had the highest 24 h mean testosterone concentrations, the best responses to exogenous LH-RH and the most differentiated testicular biopsies. Sleep had no effect on the release of LH or FSH in response to LH-RH. These sutdies suggest that the clinical and laboratory heterogeneity of idiopathic hypogonadotropic hypogonadism may be the result of differences in the degree of endogenous LH-RH deficiency.

Adult↗