There was speculation that hCG showed some FSH activity in the body because the sertoli cells would un-artophy after usage of hCG. But now we know that the sertoli cells need two things: just a little bit of FSH and testosterone. Exogenous testosterone won't cut it due to the blood barrier in the testes. But hCG has the same alpha and beta subunits as LH, and LH stimulates the leydig cells to make testosterone, thus providing the sertoli cells with the testosterone they need.