Effect of Gonadotropins and LH-RH on Functional Differentiation of Immature Monkey Testis

Transforming growth factor-beta effects on morphology of immature rat Leydig cells

Transforming growth factor-beta (TGF beta) has been shown to regulate steroid production and DNA synthesis in rat Leydig cells. We have investigated the effects of TGF beta on the secretion of extracellular matrix (ECM) proteins and on the cytoskeleton of immature rat Leydig cells in vitro. TGF beta caused significant morphological changes in Leydig cells, which were accompanied by significant increases in secretion of fibronectin, laminin and collagen IV and rearrangement of actin filaments in TGF beta-treated cells. The cells cultured on plates pre-coated with fibronectin or fibronectin plus laminin and collagen IV, displayed morphological and cytoskeletal changes similar to those induced by TGF beta. Immunofluorescence localization studies revealed significantly higher fibronectin staining in Leydig cells in adult animals and in LH-treated immature animals than those in untreated immature animals. We conclude that TGF beta participates in the morphological differentiation of immature Leydig cells into adult Leydig cells in the rat testis by inducing the expression of ECM proteins.

Effect of LHRH agonists and antagonists in male and female bonnet monkeys (Macaca radiata)

A few analogues of LHRH have been tested in the adult bonnet monkeys using change in serum testosterone following LHRH injection as a parameter of response to LHRH. Of the four analogues tested in male monkeys, Buserelin was found to be the most potent one in increasing serum testosterone levels. Injection of the LHRH antagonist at 1600 h resulted in the abolition of the characteristic nocturnal surge of testosterone observed in adult bonnet monkeys maintained under regulated light conditions. Following administration of LHRH a/s during early pregnancy, serum chorionic gonadotropin levels decreased though the course of pregnancy was not affected. These results suggest that bonnet monkey can be successfully employed to test LHRH analogues.

Effect of an LHRH analogue on testicular function in the immature monkey (Macaca mulatta)

Response of the immature monkey testis to an LHRH analogue, D-Ser-(TBu)6-EA10-LHRH, has been assessed by measuring testicular androgen production in the immature rhesus monkey. Administration of the analogue (2.5 micrograms X 2 daily) for 5 days induced a significant increase in testicular testosterone compared with untreated animals. The response of the control and the LHRH-agonist treated monkey testis to gonadotrophin (hCG) was assessed by in vitro androgen production. Whereas the testicular tissue from LHRH analogue primed monkeys responded to in vitro stimulation of hCG, no significant increase in androgen production was observed when testicular tissue from untreated animals was incubated with the gonadotrophin. The present data suggest a functional differentiation of the immature monkey testis following the LHRH analogue treatment.

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.