Autoregulation of testosterone secretion in perfused rat testes.

Infusion of testosterone into the testicular artery, at concentrations comparable to those that occur in the testicular vein in situ, inhibited LH-stimulated testosterone secretion by rat testes perfused in vitro. This inhibition was rapid and dose responsive. In contrast to testosterone, intra-arterial infusion of 5 alpha-androstan-3 alpha, 17 beta-diol, corticosterone and androstenedione failed to inhibit testosterone secretion. The inhibition of testosterone secretion by intra-arterial infusion of testosterone was reversed by either cessation of testosterone infusion or the simultaneous addition of androstenedione to the artificial perfusion medium. Taken together, these results showed that LH-stimulated testosterone secretion by in vitro perfused rat testes was inhibited by a short-loop negative feedback of testosterone.