ABSTRACT
We investigated the effect of intratesticularly injected propranolol on testicular interstitial fluid (TIF) formation and on testosterone levels in the TIF of intact adult male Wistar rats (4-9 rats per group). D1-propranolol at doses of 0.6, 1.2 or 6.0 mg/kg was injected into the left (L) testis whereas the right (R) testis (control testis) received vehicle. d1-propranolol (6.0 mg/kg) caused a significant increase in both TIF volume (329 per cent) and TIF levels of testosterone (257 per cent) in the L testis but not in the R (control) testis 3 h post-injection. In rats treated simultaneously with human chorionic gonadotropin (hCG, 5 IU/rat, sc) the same dose of propranolol (6.0 mg/kg) significantly increased the stimulatory effect of hCG on testosterone secretion by 1.8-fold, but hCG did not modify the stimulatory effect of propranolol on TIF volume. These results demonstrate a direct stimulatory effect of propranolol on TIF volume and testosterone secretion, both under basal and hCG-stimulated conditions.