| Abstract: | Orchidectomy decreased and testosterone (T) replacement restored prostaglandin E2 (PGE2) concentrations in adult rat vas deferens. To explain this finding, phospholipase A (PLase-A) and PG synthetic activity were studied in vas tissue from 9-week-old rats orchidectomized with or without T replacement as well as in rats in which the cauda epididymidis was ligated. PG synthetic activity fell to 3% of intact levels in 14-day castrate rats and was restored to normal by T replacement. Although vas PLase-A activity was also significantly (P less than 0.01) reduced to 38% of the control level in 14-day castrate rats, this change appears in part to reflect a castration-related increase in endogenous phospholipid concentrations. Further, T replacement only partially restored PLase-A activity to 59% of intact levels. Ligation of the cauda epididymidis in intact rats reduced vas PLase-A activity to castrate levels without altering vas T concentration. These results demonstrate both a direct effect of T on the biosynthesis of PGs in rat vas deferens as well as a paracrine effect, which appears to be mediated by a factor(s) other than T. These data suggest the existence of a new mechanism through which testicular products contribute to the function of the vas deferens. |
