Comparative studies on the effects of specific immunoneutralization of endogenous FSH or LH on testicular germ cell transformations in the adult bonnet monkey (Macaca radiata).

PROBLEM

It is yet to be determined clearly whether the two hormones FSH and T act synergistically in the same cell type--the Sertoli cells--to control overall spermatogenesis or influence independently the transformation of specific germ cell types during spermatogenesis in the adult mammal.

METHOD

Adult male bonnet monkeys specifically deprived of either FSH or LH using immunoneutralization techniques were monitored for changes in testicular germ cell transformation by DNA flow cytometry.

RESULTS

FSH deprivation caused a significant reduction ( > 40%; P < 0.05) in [3H] thymidine incorporation into DNA of proliferating 2C (spermatogonial) cells, a marked inhibition ( > 50%) in the transformation of 2C to primary spermatocytes (4C) and a concomitant, belated reduction (50%) in the formation of round spermatids (1C). In contrast, specific LH/T deprivation led to an immediate arrest in the meiotic transformation of 4C to 1C/HC leading to an effective and significant block ( < 90%; P < 0.01) in sperm production.

CONCLUSION

Thus, LH rather than FSH deprivation has a more pronounced and immediate effect as the former primarily blocks meiosis (4C --> 1C/HC) which controls production of spermatids. These data provide evidence for LH/T and FSH regulating spermatogenic process in the adult primate by primarily acting at specific germ cell transformation steps.