Gonadotropin-Independent Proliferation of the Pale Type A Spermatogonia in the Adult Rhesus Monkey (Macaca mulatta) In the rhesus monkey, Ap spermatogonial proliferation occurs constitutively, independent of gonadotropin stimulation, whereas differentiation of these cells into B spermatogonia is absolutely gonadotropin dependent and may be driven by either LH or FSH