Effects of Gonadotropins on Androgen Levels in Rete Testis Fluid of the Ram

Abstract

The effects of intravenously injected hCG, LH, FSH on LH + FSH on androgen levels in rete testis fluid (RTF) and peripheral blood plasma of adult conscious rams were studied. Injection of 750 IU hCG or 1 mg LH caused an increase in the concentration of androgens in both RTF and plasma, but the increase in the fluid androgen levels was proportionally much smaller. Furthermore, the elevation of androgen levels in RTF occurred later and persisted for a longer period of time than did the increase in peripheral testosterone (T) concentration. There was a significant negative correlation between pretreatment levels of T and the LH- or hCG-induced elevation in plasma and RTF androgen levels. Injection of 5 or 10 mg of FSH alone was ineffective in altering the androgen levels in RTF or plasma. Attempts to demonstrate that FSH augments the LH-induced elevation of androgen levels in the RTF were inconclusive. These results demonstrate that gonadotropins can cause acute changes in the androgen levels in the seminiferous tubules, and suggest that the concentration of androgens in the immediate milieu of spermatogenesis is much more stable than that in the peripheral plasma.