Activation of Phospholipases during Masculine Differentiation of Embryonic Genitalia

Abstract

Abstract

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.