Testicular blood flow and vasomotion can be maintained by testosterone in Leydig cell-depleted rats.

The effect of testosterone supplementation on testicular blood flow, testicular vasomotion, the number of polymorphonuclear leucocytes (PMN's) in testicular blood vessels and prostatic blood flow were studied in rats in which the Leydig cell had been destroyed specifically by a single injection of ethane dimethylsulfonate (EDS). Other rats were supplemented with testosterone by subcutaneous injection of 25 mg testosterone propionate on days 1, 3 and 6. In some experiments, the effect of a single injection of 25 or 125 mg testosterone was studied. Testicular and prostatic blood flow and the number of PMN's in testicular blood vessels decreased, and vasomotion disappeared in Leydig cell-depleted rats, but testosterone supplementation restored all parameters to normal values. Moreover, a single injection of testosterone was able to restore testicular and prostatic blood flow to normal levels but had an inconsistent effect on vasomotion. These results suggest that testosterone may play a role in the physiological control of the testicular microcirculation.