Testicular blood flow in young and old rats and influence of hCG

To evaluate the influence of age, testicular capillary blood flow (TCBF) was measured, using the microsphere technique, in rats 3 to 24 months old, under basal conditions and after hCG stimulation (10 IU/d for two days). Despite a decline in plasma T levels, testicular capillary blood flow did not decrease with age, and hCG stimulation resulted in similar increases of approximately 50% (P less than 0.01) in testicular capillary blood flow in all age groups. We concluded that the age-associated decrease in testosterone secretion in rats is not the consequence of a decreased testicular blood flow.