Direct inhibition of testicular function in rats by estriol and progesterone

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.

Endocrine manipulation in male infertility

Endocrine therapy for male infertility is broadly categorized as specific or nonspecific therapy. Although uncommon, primary endocrine diagnoses in infertile men are amenable to targeted therapy. The efficacy of empiric endocrine therapy for idiopathic male infertility, however, has not been demonstrated conclusively by clinical trials. With better understanding of the underlying pathophysiology of idiopathic male infertility, careful evaluation of endocrine therapy in well-selected treatment groups and well-designed randomized, controlled trials is warranted. Although empiric endocrine therapy for idiopathic male infertility has been largely replaced by assisted reproductive techniques, both treatment modalities could play a role, perhaps as combination therapy.

A new look at the medical management of infertility

Effective therapies are available for the treatment of infertility owing to specific causes. Most hormonal imbalances can be readily identified and successfully treated. The treatment of men with unexplained idiopathic infertility remains difficult. The availability of a multitude of agents ranging from hormones to nutritional supplements emphasizes the fact that none are consistently effective. There is no good way to predict which patients will respond to a specific treatment. Idiopathic infertility may result from multiple discrete defects in sperm generation and maturation that are as yet unidentified. A better understanding of these defects will yield more effective treatment options and appropriate triage of patients to specific therapeutic regimens. Assisted reproductive techniques remain an option for patients with idiopathic male infertility; however, they are expensive and treat the female partner for a male problem. Multiple gestations and other complications are not infrequent. Initial management should be directed at improving the quality of semen to facilitate natural conception. Specific abnormalities should be corrected. If empiric pharmacologic therapy is to be used, treatment should last at least 3 to 6 months to incorporate a full 74-day spermatogenic cycle. The infertile couple should be advised of the inconsistent response to therapy and the low conception rate that may follow when compared with the results of ART. When empiric therapy is decided upon, antiestrogens may be used and are effective in a subset of patients. The authors prefer to use clomiphene citrate, 25 mg per day. The dose may be increased to 50 or 75 mg to raise testosterone levels to the upper normal range. Lack of a significant improvement in semen parameters or of a pregnancy after a 3- to 6-month treatment period may be an indication to proceed with ART.

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.

Testicular endocrine function after withdrawal of oestrogen treatment in patients with carcinoma of the prostate

The serum concentration of testosterone, luteinising hormone (LH), follicle stimulating hormone (FSH) and prolactin were determined at different intervals after withdrawal of oestrogen treatment in patients with prostatic carcinoma. Oestrogen therapy had been stopped in all patients because of the side effects of oestrogens. There was a negative correlation (r = -0.64) between serum testosterone concentrations and the duration of oestrogen treatment in patients investigated for more than 6 months after withdrawal of hormones. However, the decrease in testosterone concentration seems to be time-dependent. Thus patients who were treated for less than 3 years had normal testosterone concentrations approximately 6 months after withdrawal of the oestrogen therapy. This group of patients had a positive correlation (r = 0.49) between serum testosterone concentration and time elapsed after cessation of therapy. In contrast, patients treated for more than 3 years retained low testosterone concentrations even after 6 months. The other hormones did not vary between the groups. It is concluded that patients with carcinoma of the prostate treated with oestrogens for more than 3 years have an impaired Leydig cell function which might be irreversible.

Estrogen receptors in the male

Estrogens in the male are secreted by the testes and derived extragonadally from the aromatization of certain androgens. In some brain regions critical for the control of gonadotropin secretion and behavior, androgens may be aromatized to estrogens within the cells that are regulated. Estrogen may have other physiological roles on the testes to control testosterone secretion and on accessory sex glands to promote both fibromuscular growth and secretion. High doses of estrogen given for treatment of prostatic cancer or modulation of reproductive function not only reduce testosterone secretion but also interact with the liver, changing the secretion of various plasma proteins and causing several undesirable side effects. The hypothalamus, pituitary, testes, accessory sex glands, and liver all contain an apparently identical protein, the estrogen receptor, which may mediate the actions of estrogen.