Feminizing effect of mesonephros on cultured differentiating mouse gonads and ducts.

Gonads were removed from fetal mice at about the time that gonadal sex differentiation occurs. The gonads were cultured in vitro with or without their mesonephric tissue. When gonads and ducts removed from sexually undifferentiated fetuses were cultured together, the gonads of both sexes developed female characteristics, whereas gonads cultured without mesonephros developed according to the sex of the fetus from which they were removed. Gonads of sexually differentiated fetuses developed whether they were cultured with or without the mesonephros.