The effect of estradiol on testicular testosterone biosynthesis

Associations of serum estradiol level, serum estrogen receptor-alpha level, and estrogen receptor-alpha polymorphism with male infertility: A retrospective study

Estradiol regulates spermatogenesis partly via estrogen receptor-alpha (ESRα). This study aimed to analyze the associations of serum estradiol level, serum ESRα level, and ESRα gene polymorphisms with sperm quality.This retrospective study included infertile men attending the Reproductive Center, Affiliated Hospital of Youjiang Medical University for Nationalities, and a control group without a history of fertility (October, 2016 to March, 2017). Data regarding sperm quality, serum levels of estradiol and ESRα, and rs2234693C/T genotype were extracted from the medical records. Pearson/Spearman correlations (as appropriate) between estradiol level, ESRα level, and sperm quality parameters were evaluated.The analysis included 215 men with infertility and 83 healthy controls. The infertile group had higher serum levels of estradiol (147.57 ± 35.3 vs 129.62 ± 49.11 pg/mL, P < .05) and ESRα (3.02 ± 2.62 vs 1.33 ± 0.56 pg/mL, P < .05) than the control group. For the infertile group, serum estradiol level was negatively correlated with sperm concentration, percentage of progressively motile sperm, and percentage of sperm with normal morphology (r = 0.309, 0.211, and 0.246, respectively; all P < .05). Serum estradiol and ESRα levels were lower in infertile men with normozoospermia than in those with azoospermia, oligozoospermia, mild azoospermia, or malformed spermatozoa (all P < .05). Sperm concentration, percentage of progressively motile sperm, serum ESRα level, and serum estradiol level did not differ significantly among the rs2234693 CC, CT, and TT genotypes.Elevated serum levels of estradiol and possibly ESRα might have a negative impact on sperm quality and fertility, whereas single nucleotide polymorphisms at rs2234693 of the ESRα gene had little or no effect.

Prenatal exposure to hexavalent chromium disrupts testicular steroidogenic pathway in peripubertal F1 rats

We have reported sub-fertility in F1 progeny rats with gestational exposure to hexavalent chromium [Cr(VI)], which had disrupted Sertoli cell (SC) structure and function, and decreased testosterone (T). However, the underlying mechanism for reduced T remains to be understood. We tested the hypothesis "transient prenatal exposure to Cr(VI) affects testicular steroidogenesis by altering hormone receptors and steroidogenic enzyme proteins in Leydig cells (LCs)." Pregnant Wistar rats were given drinking water containing 50, 100, and 200 mg/L potassium dichromate during gestational days 9-14, encompassing fetal differentiation window of the testis from the bipotential gonad. F1 male rats were euthanized on postnatal day 60 (peripubertal rats with adult-type LCs alone). Results showed that prenatal exposure to Cr(VI): (i) increased accumulation of Cr(III) in the testis of F1 rats; (ii) increased serum levels of luteinizing and follicle stimulating hormones (LH and FSH), and 17β estradiol, and decreased prolactin and T; (iii) decreased steroidogenic acute regulatory protein, cytochrome P450 11A1, cytochrome P450 17A1, 3β- and 17β-hydroxysteroid dehydrogenases, cytochrome P450 aromatase and 5α reductase proteins, (iv) decreased specific activities of 3β and 17β hydroxysteroid dehydrogenases; (v) decreased receptors of LH, androgen and estrogen in LCs; (vi) decreased 5α reductase and receptor proteins of FSH, androgen, and estrogen in SCs. The current study concludes that prenatal exposure to Cr(VI) disrupts testicular steroidogenesis in F1 progeny by repressing hormone receptors and key proteins of the steroidogenic pathway in LCs and SCs.

MALDI-IMS combined with shotgun proteomics identify and localize new factors in male infertility

In situ proteomics of male infertility.

Spermatogenesis is a complex multi-step process involving intricate interactions between different cell types in the male testis. Disruption of these interactions results in infertility. Combination of shotgun tissue proteomics with MALDI imaging mass spectrometry is markedly potent in revealing topological maps of molecular processes within tissues. Here, we use a combinatorial approach on a characterized mouse model of hormone induced male infertility to uncover misregulated pathways. Comparative testicular proteome of wild-type and mice overexpressing human P450 aromatase (AROM+) with pathologically increased estrogen levels unravels gross dysregulation of spermatogenesis and emergence of pro-inflammatory pathways in AROM+ testis. In situ MS allowed us to localize misregulated proteins/peptides to defined regions within the testis. Results suggest that infertility is associated with substantial loss of proteomic heterogeneity, which define distinct stages of seminiferous tubuli in healthy animals. Importantly, considerable loss of mitochondrial factors, proteins associated with late stages of spermatogenesis and steroidogenic factors characterize AROM+ mice. Thus, the novel proteomic approach pinpoints in unprecedented ways the disruption of normal processes in testis and provides a signature for male infertility.

Conazole fungicides inhibit Leydig cell testosterone secretion and androgen receptor activation in vitro

Conazole fungicides are widely used in agriculture despite their suspected endocrine disrupting properties. In this study, the potential (anti-)androgenic effects of ten conazoles were assessed and mutually compared with existing data. Effects of cyproconazole (CYPRO), fluconazole (FLUC), flusilazole (FLUS), hexaconazole (HEXA), myconazole (MYC), penconazole (PEN), prochloraz (PRO), tebuconazole (TEBU), triadimefon (TRIA), and triticonazole (TRIT) were examined using murine Leydig (MA-10) cells and human T47D-ARE cells stably transfected with an androgen responsive element and a firefly luciferase reporter gene. Six conazoles caused a decrease in basal testosterone (T) secretion by MA-10 cells varying from 61% up to 12% compared to vehicle-treated control. T secretion was concentration-dependently inhibited after exposure of MA-10 cells to several concentrations of FLUS (IC₅₀ = 12.4 μM) or TEBU (IC₅₀ = 2.4 μM) in combination with LH. The expression of steroidogenic and cholesterol biosynthesis genes was not changed by conazole exposure. Also, there were no changes in reactive oxygen species (ROS) formation that could explain the altered T secretion after exposure to conazoles. Nine conazoles decreased T-induced AR activation (IC₅₀s ranging from 10.7 to 71.5 μM) and effect potencies (REPs) were calculated relative to the known AR antagonist flutamide (FLUT). FLUC had no effect on AR activation by T. FLUS was the most potent (REP = 3.61) and MYC the least potent (REP = 0.03) AR antagonist. All other conazoles had a comparable REP from 0.12 to 0.38. Our results show distinct in vitro anti-androgenic effects of several conazole fungicides arising from two mechanisms: inhibition of T secretion and AR antagonism, suggesting potential testicular toxic effects. These effects warrant further mechanistic investigation and clearly show the need for accurate exposure data in order to perform proper (human) risk assessment of this class of compounds.

Mouse leydig cells with different androgen production potential are resistant to estrogenic stimuli but responsive to bisphenol a which attenuates testosterone metabolism

It is well known that estrogens and estrogen-like endocrine disruptors can suppress steroidogenic gene expression, attenuate androgen production and decrease differentiation of adult Leydig cell lineage. However, there is no information about the possible link between the potency of Leydig cells to produce androgens and their sensitivity to estrogenic stimuli. Thus, the present study explored the relationship between androgen production potential of Leydig cells and their responsiveness to estrogenic compounds. To investigate this relationship we selected mouse genotypes contrasting in sex hormone levels and differing in testosterone/estradiol (T/E₂) ratio. We found that two mouse genotypes, CBA/Lac and C57BL/6j have the highest and the lowest serum T/E₂ ratio associated with increased serum LH level in C57BL/6j compared to CBA/Lac. Analysis of steroidogenic gene expression demonstrated significant upregulation of Cyp19 gene expression but coordinated suppression of LHR, StAR, 3βHSDI and Cyp17a1 in Leydig cells from C57BL/6j that was associated with attenuated androgen production in basal and hCG-stimulated conditions compared to CBA/Lac mice. These genotype-dependent differences in steroidogenesis were not linked to changes in the expression of estrogen receptors ERα and Gpr30, while ERβ expression was attenuated in Leydig cells from C57BL/6j compared to CBA/Lac. No effects of estrogenic agonists on steroidogenesis in Leydig cells from both genotypes were found. In contrast, xenoestrogen bisphenol A significantly potentiated hCG-activated androgen production by Leydig cells from C57BL/6j and CBA/Lac mice by suppressing conversion of testosterone into corresponding metabolite 5α-androstane-3α,17β-diol. All together our data indicate that developing mouse Leydig cells with different androgen production potential are resistant to estrogenic stimuli, while xenoestrogen BPA facilitates hCG-induced steroidogenesis in mouse Leydig cells via attenuation of testosterone metabolism. This cellular event can cause premature maturation of Leydig cells that may create abnormal intratesticular paracrine milieu and disturb proper development of germ cells.

Endocrine disruptors and Leydig cell function

During the past decades, a large body of information concerning the effects of endocrine disrupting compounds (EDCs) on animals and humans has been accumulated. EDCs are of synthetic or natural origin and certain groups are known to disrupt the action of androgens and to impair the development of the male reproductive tract and external genitalia. The present overview describes the effects of the different classes of EDCs, such as pesticides, phthalates, dioxins, and phytoestrogens, including newly synthesized resveratrol analogs on steroidogenesis in Leydig cells. The potential impact of these compounds on androgen production by Leydig cells during fetal development and in the adult age is discussed. In addition, the possible role of EDCs in connection with the increasing frequency of abnormalities in reproductive development in animals and humans is discussed.

Hormonal evaluation of the infertile male: has it evolved?

An endocrinologic evaluation of patients who have male-factor infertility has clearly evolved and leads to specific diagnoses and treatment strategies in a large population of infertile men. A well-considered endocrine evaluation is especially essential with the ever-growing popularity of assisted reproductive techniques and continued refinements with intracytoplasmic sperm injection.

Reducing endogenous estrogen during development alters hormone production by porcine Leydig cells and seminiferous tubules

High levels of estrogen produced by boar testes and the presence of estrogen receptors in both interstitial and tubular compartments are consistent with a direct role for estrogen in regulation of testicular cell function. This study investigated the importance of estrogen on hormone production by Leydig cells and seminiferous tubules in the developing boar. Thirty-six 1-week-old littermate pairs of boars were treated weekly with vehicle or 0.1 mg/kg BW Letrozole, an aromatase inhibitor, until castration at 2, 3, 4, 5, 6, 7, or 8 months. Tissue was collected and Leydig cells and seminiferous tubules were isolated. In a separate study, five untreated boars (ages 1.5-4 months) were castrated and Letrozole was added in vitro to Leydig cell and seminiferous tubule cultures. Leydig cells were cultured for 24h with and without porcine LH. Media were assayed for estradiol (E(2)) and testosterone (T) concentrations by RIA. Seminiferous tubules were cultured for 4h with and without porcine FSH; media were assayed for E(2) and immunoreactive inhibin (INH). In vivo aromatase inhibition decreased basal E(2) and increased basal T production by cultured Leydig cells. Basal seminiferous tubule production of E(2) but not INH was reduced. Decreasing estrogen synthesis in vivo did not alter LH-induced Leydig cell E(2) production or FSH-induced seminiferous tubule INH production. INH production decreased with advancing age regardless of treatment. In conclusion, in vivo aromatase inhibition altered baseline steroid production by cultured Leydig cells and seminiferous tubules but had little effect on response to gonadotropins.

Role of estrogen in regulation of cellular differentiation: a study using human placental and rat Leydig cells

Estrogen classically is recognized as a growth-promoting hormone. Recent evidence suggests that estrogens are also involved in a wide variety of cellular and physiological functions involving the central nervous system, immune system, cardiovascular system and bone homeostasis. Our studies in cytotrophoblasts and BeWo cells, demonstrated that 17beta-estradiol induces terminal differentiation of placental trophoblasts directly and this differentiation is coupled with an increased production of TGFbeta1, which, in turn, affects telomerase activity and telomerase associated components at the level of hTERT. Furthermore, using rats treated in vivo with either EDS or estradiol and in vitro Leydig cell cultures, we proposed that 17beta-estradiol mediated down-regulation of collagen IV alpha4 expression could be one of the possible mechanisms for the inhibition of progenitor Leydig cell proliferation. In this review, we summarize the results from both the model systems, the human placental cytotrophoblast and rat Leydig cells to conclude that 17beta-estradiol has a unique stage-specific role in differentiation.

5alpha-reductase 2 inhibition impairs brain defeminization of male rats: reproductive aspects

The present study was carried out to determine whether 5alpha-reductase 2 (5alpha-R2) metabolic pathway plays a key role in brain sexual differentiation. The inhibition of 5alpha-R2 by finasteride (20 mg/kg/day) from gestational day 19 to postnatal day 5 has long-term effects on sexual behavior and reproductive physiology detected only in adult life. Sexual maturation assessed by timing of preputial separation was unchanged. Finasteride-treated males were able to mate with untreated females which became pregnant but exhibited increased rate of pre-implantation loss. The subfertility observed was probably due to abnormally shaped sperm, since the sperm number was not altered. While plasma testosterone was enhanced, LH levels were not changed. The copulatory potential was not affected and all finasteride-treated rats presented male sexual behavior. Despite this, 53% of them showed homosexual behavior when pretreated with estradiol, suggesting an incomplete brain defeminization. These results indicate that 5alpha-R2 acts in brain sexual differentiation of male rats. Moreover, we suggest that 5alpha-R2 not only produces essential metabolites that act together with estradiol in brain sexual differentiation but also protects the brain from the damaging effects of estradiol excess.

Insights into testicular damage induced by ethinylestradiol in rats

The present study was conducted to clarify the mechanisms of testicular toxicity induced by ethinylestradiol using a rat model maintaining testicular testosterone levels. Twelve-week-old male SD rats were implanted subcutaneously with testosterone (800 mg)-filled tubes on the back 2 days before ethinylestradiol treatment, and subsequently administered orally 10 mg/kg/day ethinylestradiol for 4 consecutive weeks. At termination, measurements of hormone levels in serum and the testis, sperm head counts in the testis, weights of genital organs and histopathological examination were performed. Results show that the supply of testosterone alone induced markedly increased serum testosterone levels, slightly decreased testicular testosterone levels, and atrophic Leydig cells. Treatment of rats with ethinylestradiol alone significantly decreased testosterone levels in serum and the testis, sperm head counts, and weights in the testis, epididymis and prostate. Histological features included atrophy of Leydig cells, decreased number of elongated spermatids, degeneration of germ cells, and tubular atrophy. Co-administration of testosterone almost completely prevented the aforementioned changes brought about by ethinylestradiol, except for Leydig cell atrophy. From these results, we attribute testicular toxicity during ethinylestradiol exposure to the suppression of testicular testosterone levels.

Improvement in spermatogenic function after subcutaneous implantation of a capsule containing an aromatase inhibitor in four oligozoospermic dogs and one azoospermic dog with high plasma estradiol-17beta concentrations

A capsule containing an aromatase inhibitor (4-androsten-4-ol-3,17-dione) was subcutaneously implanted in four oligozoospermic beagle dogs and one azoospermic beagle dog with high plasma estradiol-17beta (E2) concentrations (15-19 pg/ml) and low plasma testosterone (T) concentrations (0.6-0.8 ng/ml) for 8 weeks and the effect of the aromatase inhibitor on spermatogenic dysfunction was assessed. Plasma E2 and T concentrations and semen quality were examined at 1 week intervals from 3 weeks before to 12 weeks after the start of treatment. Testicular biopsies were done twice (capsule implantation and removal). Plasma E2 concentrations of all dogs decreased (9-14 pg/ml) and plasma T concentrations increased (2.0-2.6 ng/ml) from 3 weeks after capsule implantation to capsule removal. The mean number of spermatozoa ejaculated by all four oligozoospermic dogs between 4 and 9 weeks after implantation was higher (127 x 10(6) to 205 x 10(6)) than before implantation (20 x 10(6) to 38 x 10(6)) (P < 0.05 and 0.01). Very low numbers (2 x 10(4) to 4 x 10(4)) of immotile spermatozoa were observed between 7 and 8 weeks after implantation in the semen collected from the dog with azoospermia. Before implantation, a few spermatozoa were seen in only one-fifth of the seminiferous tubules in this dog; 8 weeks after implantation, the mean diameter and mean number of round spermatids in the seminiferous tubules in all five dogs were higher than before implantation (P < 0.05). Implantation of the capsule containing the aromatase inhibitor in infertile dogs with abnormally high plasma E2 concentrations improved their spermatogenic function, concurrent with decreased plasma E2 and increased plasma T.

Impaired Leydig cell function in infertile men: a study of 357 idiopathic infertile men and 318 proven fertile controls

To investigate whether an impaired Leydig cell function is present in severely oligospermic men, serum testosterone (T), LH, estradiol (E(2)), and SHBG levels in 357 idiopathic infertile men were compared with levels in 318 proven fertile men. In addition, the T/LH ratio, E(2)/T ratio, and calculated free T index (cFT) were compared between the two groups.A shift toward lower serum T levels, cFT, and T/LH ratio and higher serum LH, E(2), and E(2)/T levels was observed in the group of infertile men. On average, the infertile men had 18, 26, and 34% lower serum T, cFT, and T/LH levels, respectively, and 19, 18, and 33% higher serum LH, E(2), and E(2)/T levels, respectively, than the fertile men. Twelve percent of the infertile men had a serum T level that fell below the 2.5 percentile of the fertile levels, and 15% of the infertile men had a LH level that was above the 97.5 percentile of the fertile levels.Thus, the group of infertile men showed significant signs of impaired Leydig cell function in parallel to their impaired spermatogenesis. The association of decreased spermatogenesis and impaired Leydig cell function might reflect a disturbed paracrine communication between the seminiferous epithelium and the Leydig cells, triggered by distorted function of the seminiferous epithelium. On the other hand, the parallel impairment of spermatogenesis and Leydig cells may reflect a congenital dysfunction of both compartments caused by a testicular dysgenesis during fetal/infant development.

Aromatase inhibitors for the treatment of infertility

Ovarian stimulation during infertility treatment is used either alone or in conjunction with intrauterine insemination and assisted reproductive technologies. At the present time, the two main medications used for ovarian stimulation include an oral antioestrogen, clomiphene citrate and injectable gonadotrophins. In spite of the high ovulation rate, the use of clomiphene citrate is associated with adverse side effects and low pregnancy rates. In clomiphene citrate failures, gonadotrophin injections are generally the next treatment option but, especially in polycystic ovarian syndrome, are associated with increased risk of severe ovarian hyperstimulation syndrome and high multiple pregnancies. Therefore, an effective oral treatment that could be used without risk of ovarian hyperstimulation syndrome and with minimal monitoring is preferred. It was hypothesised that aromatase inhibitors can be administered early in the follicular phase to induce ovulation by releasing the hypothalamus and/or pituitary from oestrogen negative feedback. The success of aromatase inhibitors in induction and augmentation of ovulation has been reported. In addition, increased intraovarian androgen levels may synergise with central effects of decreased oestrogen to enhance ovarian response to gonadotrophin stimulation. This increased sensitivity to follicle-stimulating hormone may be especially useful in poor responders. The potential future applications for aromatase inhibitors in infertility management are also discussed.

Temporal effect of tamoxifen on cytochrome P450 side chain cleavage gene expression and steroid concentration in adult male rats

Adult male rats when treated with 0.4 mg tamoxifen (tam)/kg per day for 90 days show reduced circulating testosterone (T) and LH. The present study was designed to have an in depth understanding of tam induced androgen reduction in adult male rats. Adult male rats were orally administered 0.4 mg tam/kg per day for 30, 60 or 90 days and the temporal effects on intratesticular concentrations of pregnenolone (P(5)), progesterone (P(4)), T, 5 alpha-dihydrotestosterone (5 alpha-DHT) and estradiol (E(2)) were estimated. Control group rats were fed saline. Serum hormonal profile of LH, FSH, T and E(2) was also followed on these days. Testicular levels of cytochrome P450 scc mRNA transcripts on 30, 60 and 90 days of treatment with the same dose were quantitated by biplex RT-PCR using beta Actin as internal control followed by analysis using GelPro Analysis software.A significant reduction in intratesticular P(5), P(4), T, 5 alpha-DHT and E(2) was observed from day 30 of treatment. The P450 scc gene expression in the testis was reduced during treatment period from day 60 of treatment. This study demonstrates for the first time that tam reduces testicular pregnenolone biosynthesis through an effect on cholesterol transport and downregulation of P450 scc gene expression. In confirmation of the observed estrogenic effects of tam in this study, it is suggested that E(2) may have a role in cholesterol transport and testicular pregnenolone biosynthesis at the level of cytochrome P450 scc as shown by us.

Aromatase inhibitors for male infertility

PURPOSE

Testosterone-to-estradiol ratio levels in infertile men improve during treatment with the aromatase inhibitor, testolactone, and resulting changes in semen parameters. We evaluated the effect of anastrozole, a more selective aromatase inhibitor, on the hormonal and semen profiles of infertile men with abnormal baseline testosterone-to-estradiol ratios.

MATERIALS AND METHODS

A total of 140 subfertile men with abnormal testosterone-to-estradiol ratios were treated with 100 to 200 mg. testolactone daily or 1 mg. anastrozole daily. Changes in testosterone, estradiol, testosterone-to-estradiol ratios and semen parameters were evaluated during therapy. The effect of obesity, diagnosis of the Klinefelter syndrome, and presence of varicocele and/or history of varicocele repair on treatment results was studied.

RESULTS

Men treated with testolactone had an increase in testosterone-to-estradiol ratios during therapy (mean plus or minus standard error of the mean 5.3 +/- 0.2 versus 12.4 +/- 1.1, p <0.001). This change was confirmed in subgroups of men with the Klinefelter syndrome, a history of varicocele repair and those with varicocele. A total of 12 oligospermic men had semen analysis before and during testolactone treatment with an increase in sperm concentration (5.5 versus 11.2 million sperm per ml., p <0.01), motility (14.7% versus 21.0%, p <0.05), morphology (6.5% versus 12.8%, p = 0.05), and motility index (606.3 versus 1685.2 million motile sperm per ejaculate, respectively, p <0.05) appreciated. During anastrozole treatment, similar changes in the testosterone-to-estradiol ratios were seen (7.2 +/- 0.3 versus 18.1 +/- 1.0, respectively, p <0.001). This improvement of hormonal parameters was noted for all subgroups except those patients with the Klinefelter syndrome. A total of 25 oligospermic men with semen analysis before and during anastrozole treatment had an increase in semen volume (2.9 versus 3.5 ml., p <0.05), sperm concentration (5.5 versus 15.6 million sperm per ml., p <0.001) and motility index (832.8 versus 2930.8 million motile sperm per ejaculate, respectively, p <0.005). These changes were similar to those observed in men treated with testolactone. No significant difference in serum testosterone levels during treatment with testolactone and anastrozole was observed. However, the anastrozole treatment group did have a statistically better improvement of serum estradiol concentration and testosterone-to-estradiol ratios (p <0.001).

CONCLUSIONS

Men who are infertile with a low serum testosterone-to-estradiol ratio can be treated with an aromatase inhibitor. With treatment, an increase in testosterone-to-estradiol ratio occurred in association with increased semen parameters. Anastrozole and testolactone have similar effects on hormonal profiles and semen analysis. Anastrazole appears to be at least as effective as testolactone for treating men with abnormal testosterone-to-estradiol ratios, except for the subset with the Klinefelter syndrome, who appeared to be more effectively treated with testolactone.

Relationship between testicular transferrin and plasma estradiol-17beta concentrations of dogs with azoospermia and dogs with sertoli cell tumors

Testicular Transferrin (Tf) and peripheral plasma estradiol-17beta (E2) concentrations were measured in 3 dogs with azoospermia (AZ dogs), 3 dogs with Sertoli cell tumors (SC dogs), and 5 normal male Beagles. The mean Tf concentrations in the testes of the AZ dogs and the affected testes of the SC dogs, and the plasma E2 concentrations in both these groups of dogs were significantly higher than the values in normal dogs (P<0.05, 0.01 and 0.01, respectively). Therefore, excessive E2 secretion by hyperfunctioning Sertoli cells is thought to have caused the azoospermia in the 3 dogs.

High plasma estradiol-17beta levels in dogs with benign prostatic hyperplasia and azoospermia

The semen quality of 22 dogs (4 to 7 years old) with benign prostatic hyperplasia (BPH) was examined at the hospital of our university, and 4 of the 22 BPH dogs were diagnosed as azoospermic. The mean peripheral plasma estradiol-17beta (E2) level (17.3 pg/ml) of the 18 BPH dogs with spermatogenic function was higher than that of 5 normal male dogs and their mean T level (1.7 ng/ml) was lower. The mean E2 level (27.3 pg/ml) of the 4 BPH dogs with azoospermia was significantly higher than the value in the BPH dogs with spermatogenic function (P<0.01), and the mean T level (1.1 ng/ml) was significantly lower (P<0.05). Five normal male dogs were given 10 intramuscular injections of estradiol benzoate (E2B) 5 microg/kg, at 3-day intervals to investigate the relationship between high plasma E2 levels and the cause of the BPH and azoospermia. Their testes and prostates were measured and biopsied both before and 30 days after the start of E2B injections. At 30 days after the start of the E2B injections, the mean peripheral plasma T levels had decreased by half, and the mean testicular volume had decreased to 88% of original volume. The numbers of spermatocytes, spermatids, and spermatozoa in the seminiferous tubules of all of the dogs were significantly lower (P<0.05, 0.01). In addition, the mean prostatic volume increased to 130%, the mean height of the glandular epithelium decreased, and the glandular lumen became increased in diameter. These findings indicate that both BPH and serious spermatogenic dysfunction may be simultaneously induced by protracted high plasma E2 levels in dogs.

Estradiol acts as a germ cell survival factor in the human testis in vitro

The necessity of estrogens for male fertility was recently discovered in studies on both estrogen receptor alpha knockout and aromatase (cyp 19 gene) knockout mice. However, direct testicular effects of estrogens in male reproduction have remained unclear. Here we studied the protein expression of ERalpha and the recently described estrogen receptor beta in the human seminiferous epithelium and evaluated the role of 17beta-estradiol, the main physiological estrogen, in male germ cell survival. Interestingly, both estrogen receptors alpha and beta were found in early meiotic spermatocytes and elongating spermatids of the human testis. Furthermore, low concentrations of 17beta-estradiol (10(-9) and 10(-10) mol/L) effectively inhibited male germ cell apoptosis, which was induced in vitro by incubating segments of human seminiferous tubules without survival factors (i.e. serum and hormones). Dihydrotestosterone, which, in addition to estradiol, is an end metabolite of testosterone, was also capable of inhibiting testicular apoptosis, but at a far higher concentration (10(-7) mol/L) than estradiol. Thus, estradiol appears to be a potent germ cell survival factor in the human testis. The novel findings of the present study together with the previously reported indirect effects of estrogens on male germ cells indicate the importance of estrogens for the normal function of the testis.

Octylphenol inhibits testosterone biosynthesis by cultured precursor and immature Leydig cells from rat testes

4-tert-octyphenol (OP) is a surfactant additive widely used in the manufacture of a variety of detergents and plastic products. OP has been reported to mimic the actions of estrogen in many cellular systems. The present studies evaluated the direct effects of OP on human chorionic gonadotropin (hCG)-stimulated testosterone biosynthesis by cultured precursor and immature Leydig cells from 23-day old (prepubertal) rats. Exposure to increasing OP concentrations (1 to 2000 nM) progressively decreased hCG-stimulated testosterone formation in both precursor and immature Leydig cells at higher OP concentrations (100 or 500 to 2000 nM). Testosterone levels were reduced approximately 30 to 70% below control at the highest concentration in both cell types. Similar reductions in testosterone associated with OP exposure were observed in cells stimulated with 1 mM 8-Br-cAMP, suggesting that the main actions of OP occur after the generation of cAMP. Increasing concentrations of 17beta-estradiol (1 to 1000 nM) had no effect on hCG-stimulated testosterone formation in both precursor and immature Leydig cells and the inclusion of 100 nM ICI 182,780, a pure estrogen antagonist, in precursor and immature Leydig cells exposed to OP and hCG, did not alter the inhibition by higher OP concentrations of testosterone formation in both cell types. These results suggest that OP is a hormonally active agent, but that some of its actions are distinct from those of 17beta-estradiol and are not mediated through the estrogen receptor alpha or beta pathway. To further localize the potential site(s) of action of OP, cultured precursor and immature Leydig cells were exposed to increasing concentrations of OP and hCG for 24 h. Next, fresh media containing 1 microM 22(R)-hydroxycholesterol, 1 microM pregnenolone, 1 microM progesterone, or 1 microM androstenedione was added, and the conversion of each substrate to testosterone was determined after incubation for 4 h. The conversion of androstenedione to testosterone was unaffected by exposure to OP, suggesting that the 17beta-hydroxysteroid dehydrogenase step is not inhibited. However, the conversion of 22(R)-hydroxycholesterol, pregnenolone and progesterone all were inhibited by prior exposure to OP and hCG. This finding suggests that the 17alpha-hydroxylase/c17-20-lyase step, which converts progesterone to androstenedione, is inhibited by OP, and that the cholesterol side-chain cleavage and 3beta-hydroxysteroid dehydrogenase -isomerase steps, which convert cholesterol to pregnenolone and pregnenolone to progesterone, respectively, are other potential sites of OP action. Because concomitant exposure to the antioxidants alpha-tocopherol or ascorbate did not alter the inhibition of testosterone formation by higher OP concentrations, it does not appear that OP is acting as a pseudosubstrate for the generation of free radicals, which can damage P450 enzymes.

Azoospermia of dogs with apoptotic germ cells and Leydig cells

Apoptotic cell death in the testes of 4 dogs with azoospermia was examined. Blood plasma luteinizing hormone (LH), testosterone (T), and estradiol-17beta (E2) concentrations, and testicular transferrin (Tf) concentration as a marker of Sertoli cell function were measured in the 4 azoospermic dogs and in 5 normal dogs. The spermatids in 2 of the 4 azoospermic dogs and the Leydig cells in 3 of them exhibited apoptotic cell death. Mean LH, E2, and Tf concentrations in the 4 azoospermic dogs were significantly higher than in the normal dogs (P<0.01). These findings suggested that the azoospermia in all 4 dogs might has been caused by abnormal functions of Sertoli cells as well as Leydig cells.

Effects of estrogens and xenoestrogens on androgen production by Atlantic croaker testes in vitro: evidence for a nongenomic action mediated by an estrogen membrane receptor

The short-term effects of estrogens and xenoestrogens on testicular androgen production were investigated in an in vitro incubation bioassay system using testicular tissue from the Atlantic croaker (Micropogonias undulatus). Incubation of testicular tissue fragments with estradiol over the concentration range of 37 nM to 37 microM caused concentration-dependent decreases in gonadotropin-stimulated 11-ketotestosterone (11-KT) production. The effect was specific for estrogens; progesterone, cortisol, and the synthetic androgen mibolerone did not significantly alter 11-KT production at similar concentrations. Diethylstilbestrol, the antiestrogen ICI 182,780, and several xenoestrogens including Kepone (chlordecone), 4-nonylphenol, and a hydroxylated polychlorinated biphenyl metabolite also significantly decreased gonadotropin-stimulated 11-KT production. The action of estradiol was rapid (<5 min) and was not blocked by actinomycin D and cycloheximide, inhibitors of transcription and translation, respectively. Moreover, estradiol conjugated to BSA, which cannot pass through the cell membrane, also caused a decrease in 11-KT production. In addition, an estrogen-binding moiety was identified in testicular membrane preparations that had a single class of high-affinity (K(d) 1.6 nM), saturable (1.2 nM), displaceable, finite (B(max) 0.03 nM, 26 fmol/g testis) binding sites specific for estrogens and exhibited rapid association (t(1/2) = 5 min), characteristics typical of steroid membrane receptors. Overall the relative binding affinities of estrogens, other steroids, antiestrogens, and xenoestrogens for the membrane preparation correlated with their activities in the androgen production bioassay, thereby satisfying the final criteria for the designation of this estrogen-binding moiety as a steroid membrane receptor. The results demonstrate that estrogens and also probably xenoestrogens can act on the cell surface via a nongenomic mechanism to alter testicular androgen production in this vertebrate species.

Function of contralateral testis after artificial unilateral cryptorchidism in dogs

The effects of a cryptorchid testis on the contralateral testis were investigated after artificially producing unilateral cryptorchidism in 8 beagle dogs. Bilateral testicular biopsy and collection of spermatic vein blood and peripheral vein blood were performed at the time of the operation to produce the cryptorchidism and 52 weeks later. The testicular tissue was used for histological examination by light microscopy and measurement of the testicular transferrin (Tf) concentration by enzyme immunoassay. Plasma testosterone (T), estradiol-17 beta (E2), and luteinizing hormone (LH) levels were measured by radioimmunoassay. Semen was collected weekly and its quality was examined. No spermatogenesis was observed in the cryptorchid testes at 52 weeks after the operation, and the number of germ cells in the contralateral testes had decreased but the number of Sertoli cells did not change. The Tf concentration in both testes had also decreased. The mean total number of sperm between 48 and 52 weeks after the operation (194 x 10(6)) was less than half the number before the operation (510 x 10(6)). Mean spermatic vein plasma T levels (51 ng/ml) in the cryptorchid testes 52 weeks after the cryptorchid operation were significantly lower than before the operation (91 ng/ml; P < 0.05). By contrast, spermatic vein plasma E2 levels (80 pg/ml) were significantly higher than the values before the operation (51 pg/ml P < 0.05). The peripheral plasma LH levels decreased. These findings indicate that a large quantity of E2 secreted by the cryptorchid testis inhibits the endocrine and spermatogenic functions of the contralateral testis in the dog. In particular, it is assumed that dysfunction of the contralateral testis is associated with Sertoli cell dysfunction suggested by the low Tf concentration.

The potential roles of estrogens in regulating Leydig cell development and function: a review

It is generally agreed that estrogens, principally estradiol-17beta, are synthesized by and act in the testis of mammals, including humans. The site of estradiol synthesis in the testis is generally believed to begin in the Sertoli cell and switch to the Leydig cell during neonatal development where a gonadotropin-regulated aromatase is present. Numerous studies suggest that the primary target cell of estradiol in the testis at all ages is the Leydig cell. In fact, the Leydig cell is known to possess an estrogen receptor that binds estradiol in the classic manner. The mechanism of estradiol action and the role of its receptor in the testis, however, remain unresolved. In Leydig cells, estradiol appears to induce several alterations that are dependent in large part on the developmental stage of the Leydig cell. In the fetal and neonatal testes, estradiol appears to block the ontogenic development of Leydig cells from precursor cells. There is also evidence that estradiol similarly blocks the regeneration of Leydig cells in the testis of mature, ethane dimethylsulfonate-treated animals. Evidence indicates that the precursor cell possesses high levels of estrogen receptors relative to that of the Leydig cell. It is postulated that estradiol is a paracrine factor involved in regulating the interstitial population of Leydig cells. Evidence also indicates that estradiol acts directly in the mature testis to block androgen production. It appears to do so by inhibiting the activities of several steroidogenic enzymes involved in testosterone synthesis. Although the more conventional receptor-mediated mode of action is feasible, several studies have suggested that this action might entail direct competitive inhibition of key steroidogenic enzymes by estradiol. In summary, the net biologic effect of estradiol in the testis appears to be inhibition of androgen production, either by limiting development and growth of the Leydig cell population or through direct action in the Leydig cell.

Epididymal sperm motion as a parameter of male reproductive toxicity: sperm motion, fertility, and histopathology in ethinylestradiol-treated rats

The present study was designed to characterize the effect of ethinylestradiol (EE) on epididymal sperm motion using a computer-assisted sperm analysis system (CASA), and to elucidate the correlation between sperm motion endpoints and other measures including fertility, histopathologic, and endocrinologic endpoints. EE was orally given to adult male rats at a daily dosage of 10 mg/kg for 3 and 5 d, and at daily dosages of I and 10 mg/kg for 1, 2, 3, and 4 weeks. Changes in sperm motion were first detected after one week of treatment. Of nine sperm motion parameters, the percentage of motile sperm, velocity, and amplitude of the lateral head displacement (ALH) were decreased in the 10 mg/kg dosing group. Accompanying the decreases in those parameters, the male fertility indices in the 10 mg/kg dosing group were reduced after one week of treatment, and no males in this group could impregnate intact females after 2 weeks or more of treatment. The number of sperm heads in the cauda epididymis in the 10 mg/kg dosing group was reduced to about one-half that in the control group after one week of treatment, whereas the total number of homogenization-resistant advanced spermatids in the testis was not altered and only a slight change was detected in the number and morphology of germ cells in the testis. These results suggest that reduction in the number of epididymal sperm and in sperm motion are not secondary to testicular alteration. However, after 3 weeks of treatment, the number of sperm heads in the testis was drastically reduced with severe atrophy of the seminiferous tubules both in the 1 and 10 mg/kg dosing groups. The profiling of epididymal luminal fluid proteins indicated that two major bands that migrated with molecular weights of about 22 and 23 kDa were weakened and their density was reduced to approximately 70% of the control after 5-d and one week treatments in the 10 mg/kg dosing group. Circulating testosterone declined drastically after 3 d of treatment and remained at undetectable levels with a concomitant decline of circulating LH and FSH, suggesting that EE inhibits testosterone secretion immediately via a negative feedback system, and there follow changes in the accessory reproductive organs including the epididymis. These results indicate that EE affects epididymal spermatozoa before testicular germ cells via a testosterone deficiency, when it is administered at extremely high dosages. The reduction in the sperm motion manifested as decreases in the percentage of motile sperm, ALH, and velocity, is considered to be responsible for the onset of infertility. Sperm motion analysis could be particularly useful for detecting the toxic effects of chemicals that act through the endocrinologic system on the epididymis.

Cellular localization and regulation of expression of testicular estrogen sulfotransferase

Estrogen sulfotransferase (EST) is a cytosolic enzyme that catalyzes the specific sulfonation of estrogens at the 3-hydroxyl position using 3'-phosphoadenosine-5'-phosphosulfate as an activated sulfate donor. Sulfated estrogens no longer bind to the estrogen receptor and are, therefore, hormonally inactive. Although liver has been considered a primary site for steroid sulfotransferase activities, we previously have cloned the mouse EST complementary DNA and found the enzyme to be expressed abundantly in the testis of normal mice. In this study we show by reverse transcription-PCR that EST is also expressed in the testes of rat and man, suggesting that testicular expression of EST may be a common phenomenon among different species. Using a purified polyclonal antibody raised against the bacterially expressed mouse EST protein, we demonstrate by immunohistochemistry that EST is localized selectively to the androgen-producing Leydig cells within the mouse testis. Additionally, we show that Leydig cell expression of EST is under the control of the pituitary hormone LH and is regulated differentially during development. In contrast to the high level of expression in mature intact animals, EST is not present in Leydig cells of hypophysectomized mice or in Leydig cells of fetal and prepubertal (day 5 or 17) mouse testes. Administration of hCG to hypophysectomized mice restored the testicular expression of EST. Together, these results suggest that testicular expression of EST may play an important role in male reproduction, conceivably by modulating the activity of locally synthesized estrogen in the testis of a sexually mature animal.

Perinatal estrogen exposure: later repercussion on the fertility of rats

The aim of the present study was to investigate the effects of perinatal estrogen exposure in the fertility of rats. Thus, rats were treated with estrogen on the 21st or 22nd day of intra-uterine life or treated with estrogen immediately after birth. It was observed that the testicular descent of males and beginning of puberty of females were advanced in all estrogen-treated groups. The females from estrogen-treated groups showed reduced frequency of estrous in 15 consecutive days of study, and there was an increase in estrous duration. Their fertility also were impaired and a reduction in the number of alive fetuses, as well as enhancement of pre- and postimplantation loss, mainly in the group treated with estrogen on the 21st day of intra-uterine life. However, the alterations observed in the fertility of estrogen-treated male rats were slighter and only females mated with male rats from the group treated with estrogen immediately after birth showed enhanced preimplantation loss. We suggest that the reproductive function is impaired by exposure to estrogen in the perinatal life of rats, and that the mechanisms involved in this effect are distinct for males and females.

Association of elevated estradiol with remote testicular trauma in young infertile men

OBJECTIVE

To determine the incidence of remote testicular trauma and of possible related permanent hormonal and seminal changes in infertile men.

DESIGN

Retrospective clinical study of hormonal and seminal parameters in a subpopulation of infertile men.

SETTING

Andrology Clinic in an academic research environment.

PARTICIPANTS

Infertile men, with and without history of remote testicular trauma, and fertile volunteers.

MAIN OUTCOME MEASURES

Percentage of infertile men with history of blunt testicular trauma, concentrations of reproductive hormones, and semen parameters.

RESULTS

Significant remote blunt testicular trauma was reported by 16.8% of infertile men. This had occurred 2 to 17 years (mean, 16.4 years) before evaluation, mostly with contact sports at adolescent age. Estradiol concentrations after testicular trauma were 19% and 25% higher than in infertile men without history of testicular injury and in fertile controls. Elevated E2 levels did not correlate with T. Infertile men with and without history of testicular trauma showed changes in seminal parameters.

CONCLUSION

The incidence of remote blunt testicular trauma in infertile men is unexpectedly high. After injury, FSH-stimulated aromatization of T may increase testicular E2 production, interfere with spermatogenesis, and cause infertility. Consistent use of protective devices in contact sports is recommended.

Effect of obesity and fertility status on sex steroid levels in men

Endocrine studies were performed on fertile and infertile obese men and compared with fertile and infertile nonobese men in order to determine the independent and codependent effects of obesity and fertility status on the male hypothalamic-pituitary gonadal axis. The obese infertile group exhibited significant endocrinologic changes as compared with fertile nonobese control group which was not observed in any of the other three groups. Serum testosterone was significantly lower. The testosterone/estradiol ratio was significantly lower despite a lack of significant change in serum estradiol levels. Serum steroid hormone binding globulin (SHBG) was significantly lower which correlated with elevated bioavailability of both testosterone and estradiol in the obese infertile group. Serum luteinizing hormone levels were no different, suggesting that free testosterone levels were unchanged. Obese infertile men exhibit endocrinologic changes that are not observed in men with either obesity or infertility alone. Reduction of serum SHBG, total testosterone, and testosterone/estradiol ratio appear to be a marker of infertility among obese men.

Suppression of plasma testosterone and prostate carcinoma size by a redox-based, brain-targeted estrogen delivery system in the rat

Studies were undertaken to examine the effects of an estradiol-chemical delivery system (E2-CDS) or castration (CAST) on plasma testosterone (T) and growth of the Segaloff 11095 carcinoma. Fischer 344 rats were implanted subcutaneously with the Segaloff 11095 tumor and tumor growth was monitored thereafter. After optimal tumor growth, when the average tumor size was approximately 25 x 15 mm (length x width; 4-5 g wet weight), rats were randomized into (1) testis-intact controls; (2) CAST; (3) intact+E2-CDS groups (rats received weekly injection of the E2-CDS at 0.5 mg/kg). Animals were killed 7 or 14 days after the initiation of treatments. Blood and tissue samples were collected for subsequent analysis. Plasma T levels were suppressed by 98% and 97% through 14 days after CAST or E2-CDS treatment. CAST increased plasma gonadotropin (LH) concentrations, while E2-CDS reduced LH compared to intact control levels. E2-CDS treatment increased plasma E2 levels to 24 (one injection) or 75 pg/ml (two injections) at 7 or 14 days, respectively. E2-CDS, given once a week for 2 consecutive weeks, resulted in a decreased growth of the prostate tumor by 61%, while CAST reduced the weights of these tumors by only 20%. In response to E2-CDS (one or two injections), weights of the in situ ventral prostate and seminal vesicles were significantly reduced by 70% and 50%, respectively, in tumor-bearing rats. Similarly, CAST reduced the weights of these tissues by 80% (prostate) or 52% (seminal vesicle) at 7 or 14 days after treatment. Pituitary weight increased, while testes weight decreased by 20% with two injections of E2-CDS, compared with intact control rats. Collectively, these data indicate that E2-CDS is effective in reducing the growth rate of prostatic tumors in the rat.

Routine hormone load tests are unnecessary in infertile men

A sample of 225 men examined at the Infertility Service Unit of this hospital had spermiograms, standardized in accordance with WHO guide lines, and a hormone stimulation test with injection of gonadotropin releasing hormone, thyrotropin releasing hormone, and ACTH. The serum concentrations of the following hormones were assessed: follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, oestradiol (E), thyroid stimulating hormone, cortisol, 21-desoxycortisol, 17-hydroxypregnenolone, 17-hydroxyprogesterone, dehydroepiandrosterone, dehydroepiandrosteronesulphate, androstenedione, testosterone (T), and dihydrotestosterone. The results of the spermiograms were found to be related to the concentrations of the following hormones: FSH, LH, T, and E. Thyroid and adrenal function in men without signs of endocrinological diseases failed to influence spermatic parameters.

Hormone load tests in infertile male patients

The recognition that discreet hormonal abnormalities may cause ovulation disorders in women suggested that the male partner of infertile women might also suffer from unrecognized hormonal dysfunction amendable to substitution therapy. We obtained a combined stimulation test with gonadotropin-releasing hormone (GnRH), thyreotropin-releasing hormone (TRH), and ACTH in 225 males with childless spouses, when the couple sought to have children for at least one year. The following hormone levels were determined: estradiol (E), thyroid-stimulating hormone (TSH), prolactin, testosterone (T), dihydrotestosterone (DHT), androstenedione(A), 17-OH-pregnenolone (17-OH-Preg), 17-OH-progesterone (17-OHP), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), cortisone (F), and 21-desoxycortisone (21DF). Basal and stimulated, and adrenal-testicular steroids with and without ACTH stimulation failed to demonstrate a relevant relationship to semen parameters. Gonadotropin levels had a significant negative correlation to all important semen parameters (testicular volume, sperm count, motility, morphology, and vitality) and were positively correlated to spermiogenetic defects. Stimulated LH values were more clearly associated with spermiogenetic defects than basal LH. Nonetheless, basal FSH concentrations were more informative than LH. Stimulated prolactin values were positively correlated with both gonadotropin and with sperm morphology. E concentrations had a significant positive correlation with both basal and poststimulation DHEAS values, and showed a highly negative correlation with sperm count, morphology, and vitality. In comparison, good sperm parameters were associated with high poststimulation T concentrations. The results of this study suggest that basal FSH and E concentrations, as well as the stimulated LH, T, and prolactin determinations, should be included in the evaluation of male sterility.

Morphological effects of the catecholestrogens on cells of the seminiferous tubules of Sprague-Dawley rats

Estradiol-17 beta (E2) and the two catecholestrogens 2-OHE2 and 4-OHE2, when daily administered at low doses of 10-40 ng/rat, were cytotoxic to the seminiferous epithelium. The structural changes seen after seven days exposure included abnormal meiotic type II cells with uneven chromosome distribution, the formation of binucleated and multinucleated giant cells, of which many were sloughed into the lumina of the seminiferous tubules. The effect of the 4-OHE2 metabolites were always more pronounced that that of 2-OHE2 or E2. After 21 daily exposures, 4-OHE2 proved to be very toxic, the seminiferous tubules were markedly denuded and numerous giant cells were present in the lumina. The catecholestrogens also caused a significant lowering (P less than 0.02) of testosterone serum levels after eight days exposure. E2 at 40 ng/rat/day had no effect on testosterone production. At these low doses the catecholestrogens did not affect gonadotropin release after eight days exposure. Our results indicate that the morphological lesions could not exclusively be attributed to testosterone withdrawal and that a direct effect on developing spermatids is also indicated.

Selective inhibition of cytochrome P-450 in rat testicular microsomes: effect of cobalt-protoporphyrin on progesterone metabolism

Cobalt-protoporphyrin (CoPP) administration to adult male rats results in a profound reduction in hepatic cytochrome P-450 concentration and activity, and decreased plasma concentrations of testosterone and luteinizing hormone (LH). The metabolism of progesterone by rat testicular microsomes isolated 48 h after treatment in vivo with CoPP was compared to that in microsomes from control rats. The conversion of progesterone to 17 alpha-hydroxyprogesterone and 4-androstenedione, which is NADPH-dependent, was reduced by approximately 40% in testicular microsomes following treatment with CoPP (50 mumol/kg body weight) and this inhibition was dose-dependent. The concentration of cytochrome P-450 in testicular microsomes and the activity of 7-ethoxycoumarin de-ethylase (a cytochrome P-450 dependent function) were also reduced following treatment with CoPP in contrast to two other functional assays of cytochrome P-450, aryl hydrocarbon hydroxylase and ethylmorphine demethylase, which were unaffected by treatment with CoPP. Thus, the profound effect of CoPP on androgen homeostasis has been extended to include decreased testicular synthesis of 4-androstenedione in addition to increased hepatic metabolism of testosterone, attenuated pituitary LH release in response to luteinizing hormone-releasing hormone, and failure of testicular response to LH.

Hypogonadism following long-term treatment with diethylstilbestrol

The authors describe the abnormalities of gonadal function developing in a patient with prostate cancer who had received estrogen therapy continuously for 6 years. The pretreatment prostate biopsy showed well developed acini consistent with normal androgenization and adenocarcinoma. Twelve years later, 6 years after discontinuation of estrogen treatment, the patient presented with severe hypogonadism, gynecomastia, and primary hypothyroidism. Testicular biopsies showed ghosts of seminiferous tubules with absence of Leydig cells, and prostatic biopsies showed atrophic acini without evidence of malignancy. Despite undetectable serum testosterone levels, serum gonadotropins were inappropriately normal and responded minimally to gonadotropin-releasing hormone (GnRH) administration. Replacement therapy with levothyroxine did not correct gonadal dysfunction. Thus, prolonged estrogen therapy may result in irreversible testicular destruction and loss of the feed-back response of the hypothalamic pituitary gonadal axis.

Treatment of men with idiopathic oligozoospermic infertility using the aromatase inhibitor, testolactone. Results of a double-blinded, randomized, placebo-controlled trial with crossover

The hypothesis that increased estradiol production may be the cause of impaired spermatogenesis in infertile men with idiopathic oligozoospermia was tested by administering the aromatase inhibitor, testolactone, and by assessing its effects on sperm output and fertility. Our study was a randomized, placebo-controlled double-blind crossover trial. Subjects (n = 25) with infertility due to unexplained oligozoospermia were given testolactone (2 g/day) or placebo for 8 months followed by crossover to the other treatment for an additional 8 months. Total estradiol and testosterone levels during testolactone exposure did not change from basal and placebo values. However, sex hormone-binding globulin binding capacity consistently decreased (30%, p less than 0.01) and free testosterone levels increased (36%, p less than 0.01). Free estradiol values increased but not significantly. Additionally, LH and FSH serum levels increased by 15% and 20%, respectively (p less than 0.05), and 17 alpha-hydroxyprogesterone values increased by 90% (p less than 0.05) during drug administration. Sperm output and semen quality remained unchanged during either testolactone or placebo treatment, and no pregnancies occurred during the 16-month study. These data suggest that chronic administration of testolactone at this dose fails to maintain aromatase inhibition despite depression of 17,20-desmolase activity with elevated 17 alpha-hydroxyprogesterone and depressed SHBG binding capacity with elevation of free testosterone. Testolactone is not efficacious in the treatment of idiopathic oligozoospermic infertility.

Time-dependent effects of alcohol on the hypothalamic-hypophyseal-testicular function in the rat

Adult male rats were followed throughout ethanol administration, in order to examine the time-dependent effects of ethanol on the hypothalamic-pituitary-gonadal axis. The results indicate that there is an increase in plasma prolactin levels together with a reduction in basal plasma luteinizing hormone (LH) levels, which are evident from the beginning of the intoxication period. An exaggerated response of LH to luteinizing hormone-releasing hormone was also evident from 2nd week on, in ethanol-treated rats. Basal and human chorionic gonadotropin-stimulated plasma testosterone levels were decreased in alcohol-treated as compared to control rats, at all time points studied. In addition, plasma estradiol levels were increased in ethanol-fed rats. These data suggest a direct suppressive effect of ethanol on LH release in the beginning of the intoxication period. Subsequent elevations of plasma estradiol and prolactin levels may have contributed to the maintenance of hypogonadism at the end of the intoxication period.

Dynamics of estradiol and testosterone and seminal fluid indexes in smokers and nonsmokers

The serum levels of estradiol (E2) and testosterone (T), the metabolic clearance rates of estradiol (MCRE2) and testosterone (MCRT), and the production rates of estradiol and testosterone (PRE2) and (PRT) were examined in 22 male smokers and 21 male nonsmokers. Seminal fluid indexes (sperm count, % motility, grade of motility, and % of sperm with abnormal morphology) were also assessed. The mean E2 level and the mean PRE2 were significantly greater in smokers than in nonsmokers (P less than 0.001 and P less than 0.01, respectively); however, the means of MCRE2, MCRT, PRT, and T did not differ significantly in smokers compared to nonsmokers. No significant product-moment correlations were found between the various hormonal measures and the seminal fluid indexes in the overall sample. However, the smokers with sperm counts below the median sperm count of the sample had significantly higher mean levels of E2 and PRE2 than did the smokers with sperm counts above that median. Mechanisms that might mediate the greater PRE2 of smokers and a negative relationship between estradiol and sperm count are discussed.

Effects of a brain-enhanced chemical delivery system for estradiol on body weight and serum hormones in middle-aged male rats

We have developed a redox-chemical delivery system for brain-enhanced drug delivery of estradiol based on an interconvertible dihydropyridine in equilibrium pyridinium salt carrier. Estradiol, when combined with the carrier, readily crosses the blood-brain barrier and upon oxidation of the carrier is "locked" in the brain. The aim of this study was to evaluate the effects of the estradiol-chemical delivery system (E2-CDS) on body weight change and associated alterations in the secretion of anterior pituitary hormones in middle-aged, male rats. The data revealed that rats receiving E2-CDS exhibited a significant weight loss by 2 days which continued to day 14, the last observation day. A significant weight difference was observed between E2-CDS and DMSO-treated animals. Serum estradiol levels of rats treated with E2-CDS were elevated 100-fold by day 1 and decreased thereafter and serum prolactin concentrations were doubled by 24 hours and continued to increase to the completion of the experiment. Testosterone levels were markedly suppressed by 24 hours while serum levels of LH, TSH, T3, T4 and GH were not significantly altered. These data indicate that the E2-CDS causes a long-term reduction in body weight and testosterone secretion and that these changes are not mediated by alterations in the secretion of anterior pituitary hormones.

Studies on low molecular weight follicle stimulating hormone receptor binding inhibitor (FSH-RBI) from ovine testis

Follicle stimulating hormone receptor binding inhibitor (FSH-RBI) has been isolated from the aqueous extracts of ovine testis using Sephadex column chromatography. Sephadex G-75 fraction IV was found to inhibit the binding of (125I) FSH to rat testis receptors. Further purification of Sephadex G-75 fraction on Sephadex G-25 column gave three fractions (I-III). The maximum inhibitory activity to inhibit (125I) FSH binding to rat testis receptor was associated with fraction III only. FSH-RBI exerted a greater inhibitory effect on the formation of the hormone-receptor complex rather than on the dissociation of the preformed complex. FSH-RBI did not inhibit the binding of (125I) LH to rat testis receptors. A significant decrease in the mouse ovarian weight was observed when FSH-RBI was injected to hCG-primed female mice. The molecular weight determination studies show that molecular weight of FSH-RBI is approximately 1400 Daltons.

Feminizing Leydig cell tumor: endocrine and incubation studies

A 32-year-old patient with a history of surgery for left gynecomastia four years previously presented with right gynecomastia; a tumor in the left testis proved to be a Leydig cell tumor. Preoperative investigations showed elevated but variable levels of plasma estradiol (E2) and estrone (E1), and reduced serum LH and FSH and plasma testosterone (T). After hCG stimulation, E2 response was increased and abnormally prolonged; T reached normal values, which has predictive value for a return to normal of post-operative T level. After left orchiectomy, gynecomastia regressed within a few days, gonadotropins increased by day 2, estrogens dropped by day 2 and were normal at day 7, T and 5 alpha-dihydrotestosterone dropped at day 2 but reached normal levels at day 16. Pathophysiology of these hormonal data are discussed. An incubation procedure with 3H testosterone showed an aromatase activity 21 times greater in the tumor than in normal peritumoral tissue, while the percentage of the volume occupied by Leydig cells was 34 times higher. This suggests that the aromatase activity of a single tumor cell is very similar to that of a normal Leydig cell. Furthermore, evidence of juxtatumoral Leydig cell hyperplasia in areas where the tumor was well encapsulated suggests the existence of a factor stimulating Leydig cell multiplication.

Serum testosterone concentrations in men with alcoholic cirrhosis: background for variation

Median serum testosterone concentration of men with alcoholic cirrhosis (n = 216) did not differ significantly from normal controls (n = 51), but serum testosterone concentrations varied by a factor 43.9 in patients compared to 3.2 in controls (P less than .001). Nineteen percent of the patients had serum testosterone concentrations above 30 nmol/L. Serum concentrations of sex-hormone-binding globulin (SHBG) were significantly (P less than .001) raised, and serum concentrations of calculated nonprotein-bound and non-SHBG-bound testosterone were significantly (P less than .001) decreased in patients compared to normal control values. A number of background variables were analyzed with reference to serum testosterone concentrations by means of multiple regression techniques after having divided the patients into groups (A, B, C) with decreasing liver function by a modification of the Child-Turcotte's criteria. The only significant (P less than .01) background variables associated with log serum testosterone concentrations were: group C (beta = -0.828), group B (beta = -0.222), age (years) (beta = -0.012), duration of hospitalization (days) (beta = -0.0077), and concentration of SHBG (nmol/L) (beta = 0.0044). Neither previous nor recent (within last six months) alcohol consumption influenced serum testosterone concentrations significantly, but about 50% of the patients had abstained from ethanol for two months or more. The same background variables as above were included as significantly (P less than .01) associated with log serum concentrations of calculated nonprotein-bound testosterone and calculated non SHBG-bound testosterone, except that SHBG was insignificantly associated to any of the two proportions and that testicular volume was significantly (P less than .05) associated with log non-SHBG bound testosterone.(ABSTRACT TRUNCATED AT 250 WORDS)