Effect of the interstitial-cell-stimulating hormone on testicular enzymes during spermatogenesis

✍ Scribed by Hitzeman, Sister Jean Walter

• Publisher: John Wiley and Sons
• Year: 1968
• Tongue: English
• Weight: 785 KB
• Volume: 169
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401690307

✦ Synopsis

The activities of 17P-hydroxysteroid dehydrogenase and of some NADPH-generating enzymes in the fetal mouse testis during the formation of the accessory reproductive glands indicate that Leydig cells synthesize androgens before gonadotropins are secreted. In the neonatal testis the seminiferous tubules grow rapidly and the relative volume of the intertubular tissues decreases. At the same time the absolute activity of 17PSDH also decreases but there is no evident loss of enzyme activity as the primary spermatocytes begin meiotic prophase. High levels of NADPHgenerating malic enzyme activity coincide with the onset of meiosis and the development of the spermatids, although the activity of 17PSDH remains constant. Both glucose-6-phosphate and isocitrate dehydrogenases, which can be activated by gonadotropin, show strong activity prior to spermiogenesis.

Significantly increased activities of 17pSDH and the ME occur in 10-day postpartum intact mice four hours after a single injection of 0.25 unit ICSH. Exogenous gonadotropin stimulates GGPDH and IDH activities during divisions of spermatogonia five days after birth. The pituitary-Leydig cell axis i s stabilized after the beginning of meiosis so exogenous ICSH has little effect on testicular enzymes during the remainder of the first wave of spermatogenesis. Dependence of Leydig cell activities on pituitary gonadotropin seems to occur during pachytene or the early stages of spermatid formation. Androgen synthesis in the murine testis may be associated with the NADPH-generating ME and IDH as well as G6PDH which has been implicated in other steroidogenic tissues.