Hormonal Regulation Of Spermatogenesis Research Articles

Characterization of human Sertoli cells in vitro.

The Sertoli cell is thought to play a significant role in the hormonal regulation of spermatogenesis within the rat testis. Little, however, is known about Sertoli cell function in man, largely because of the difficulties associated with the isolation of pure cell populations from human tissue. We have now developed a rapid and reproducible technique for establishing a human Sertoli cell monolayer culture. This has involved mechanical separation of the tissue, sequential trypsin and collagenase enzyme digestion, and final disruption of tubules by passage through a wire mesh grid. Using this technique, primary cultures can be maintained for up to 45 days. Ultrastructural studies of these cells have demonstrated the presence of the perinucleolar spheres, cell to cell junctional complexes, abundant lipid droplets, and smooth endoplasmic reticulum, all characteristic of Sertoli cells. Furthermore, biochemical markers of animal Sertoli cells, androgen-binding protein and gamma-glutamyl transpeptidase, have also been identified in these human cells. Concentrated media electrophoresed on nondenaturing gels containing 2 nM [3H]dihydrotestosterone produced a single peak of bound activity which coelectrophoresed with rat androgen-binding protein. This binding activity persisted despite media changes, thus ruling out contamination by serum binding proteins; fresh media lacked demonstrable binding activity. Using a colorimetric assay, these cells were also found to contain significant gamma-glutamyl transpeptidase activity compared to human foreskin fibroblasts and Leydig cells. Enzyme activity increased in a characteristic dose-response fashion in the presence of FSH (0.05-0.5 microgram/ml) and dibutyryl cAMP (0.1-1 microgram/ml), but not with LH or testosterone. These data offer the first demonstration of human Sertoli cells in monolayer culture and their production of a marker specifically regulated by FSH.

The effect of levonorgestrel and estrone rods on male reproductive function.

The effect on spermatogenesis of the implantation of six rods containing levonorgestrel and three estrone rods was studied in seven volunteers aged 32-40, with normal pre-treatment spermiogram. None of the subjects achieved azoospermia. The lowest sperm count was below 1 million/ml in three subjects and below 12 million/ml in the other four. Plasma FSH and testosterone were severely depressed during the study, but LH was only transiently depressed for the first two months. Four subjects recovered pre-treatment sperm counts in spite of the FSH levels below 1.5 mIU/ml and testosterone levels below 1 ng/ml, which is contradictory to the current concept on hormonal regulation of spermatogenesis.

Hormonal Regulation of Spermatogenesis

Publisher Summary This chapter discusses the hormonal regulation of spermatogenesis. The hormonal regulation of spermatogenesis involves interplay of sex steroids and pituitary gonadotropic hormones acting on specific cells of the testis. The target cells for pituitary hormones and steroid hormones within the testis and to the elucidation of molecular mechanisms for hormone action are identified. The mechanisms involved in the hormonal control of Sertoli cells and the interaction between Sertoli cells and germ cells are also reviewed in the chapter. Androgenic hormones provide a major stimulus for spermatogenesis. Production of testosterone by Leydig cells is regulated by interstitial cell-stimulating hormone (ICSH). Leydig cell development and steroidogenic function may require a direct action of testosterone or dihydrotestosterone. Prolactin and follicle-stimulating hormone (FSH) enhances Leydig cell responsiveness whereas estrogen appears to inhibit Leydig cell response to ICSH with respect to steroidogenesis. Androgens stimulate peritubular cell differentiation and the development of tubular contractions. Androgens and FSH regulate Sertoli cell function.

Hormonal control of mammalian spermatogenesis.

Studies of the hormonal control of the spermatogenic process are reviewed. Most of the investigations used the techniques of ablation and replacement therapy and were performed on the rat. Results from the studies indicate that changes in the metabolism of proteins lipids and carbohydrates take place in the testes under the control of hormones. However it may be that the observed biochemical changes which occur are a reflection of the changes in cellular composition of testicular tissue rather than the result of metabolic changes within a specific cell type in response to the effect of a hormone. A hypothesis concerned with the qualitative aspects of hormonal control of spermatogenesis in the rat has been formed. It is proposed that the multiplication and growth of gonocytes prenatally and in the first few days after birth and formation of type A spermatogonia are under the control of testosterone. The formation of type A and B spermatogonia and primary spermatocytes and progression of the meiotic prophase may be influenced by growth hormone. Reduction division is under control of testosterone. The early steps of spermatid formation may be under no hormonal control or may require testosterone while the late stages of spermatid maturation require the presence of FSH.