Effects of gonadotrophin treatment in vivo on testicular function in immature rhesus monkeys (Macaca mulatta).

Changes in testicular histology and concentrations of testosterone and oestradiol 17 beta in testicular tissue and plasma have been studied following administration of gonadotrophins (oFSH, oLH, hCG and PMSG) to immature male monkeys. Treatment with FSH (1 mg/day) or PMSG (100 IU/day) for five days, induced a marked enlargement of the seminiferous tubules and increase in the Sertoli cell cytoplasm. Injections of LH (1 mg/daily) or hCG (100 IU/daily) administered similarly, failed to produce hypertrophy of the Sertoli cell. In LH, hCG and PMSG stimulated testes morphologically differentiated interstitial cells could be recognized. FSH did not produce any detectable effect on the intertubular tissue. A significant increase in testicular and plasma testosterone levels was observed with LH, hCG and PMSG. FSH was shown to be much less effective in stimulating androgenesis. An increase in testicular oestradiol production over that of controls, was observed in FSH and PMSG treated monkeys but not in animals treated with LH or hCG.