Activation of phospholipases during masculine differentiation of embryonic genitalia

We have investigated whether the androgen-induced masculine differentiation of the sex organs involves an induction of phospholipases. We have measured phosphatidylinositol-specific phospholipase C and phosphatidylcholine-specific phospholipase A2 in the reproductive tract of male and female mouse (CD-I) fetuses at the 18th day of gestation. We report here that (1) the activity of these two enzymes is higher in the male genitalia than in the female genitalia; (2) exogenous testosterone at the 13th to 17th day of pregnancy induces both phospholipase A2 and phospholipase C in the female fetal genitalia; and (3) prenatal administration of cyproterone acetate, an antiandrogen, known to produce feminized males, completely prevents the stimulation of phospholipase A2 and C by testosterone in the female fetuses. In the male fetuses, however, cyproterone acetate inhibits the PLC activity but is unable to alter phospholipase A2 activity. These findings provide evidence that the mechanism by which testosterone organizes the genitalia may involve a modification of phospholipases A2 and C.