Effects of testosterone and estradiol on prostaglandin E synthesis by rat kidney medulla

When prostaglandin E (PGE) contents in kidney medullary tissue were determined, we found that the PGE level was significantly higher in the male rats. The activity of PG synthetase in kidney medullary microsomes to synthesize PGE2 and the effect of treatment with sex hormones on the activity were also investigated. There was no significant difference in PG synthetase activity between male and female intact rats. Subsequently, ovariectomy and orchidectomy wee carried out and corn oil (control group), testosterone (2.0 mg/kg) or estradiol (0.2 mg/kg) were given subcutaneously every other day for 2 weeks. Testosterone treatment produced a significant increase in the activity of PG synthetase in males, but not in females, when compared with control values. In contrast, estradiol treatment produced a significant decrease in PG synthetase activity in both sexes. These results suggest that sex hormones may play an important role in the regulation of PG biosynthesis in kidney.