PERINATAL-DEVELOPMENT OF GUBERNACULAR CONES IN RATS AND RABBITS - EFFECT OF EXPOSURE TO ANTI-ANDROGENS

In male rats gubernacular cones develop during the latter half of pren atal fife. Inversion of these papilla-like organs after birth is the f irst step to postnatal growth of the muscular cremaster sacs. The fact ors regulating prenatal growth and differentiation or postnatal invers ion of these gubernacular cones are unknown. The lack of a detailed an d unequivocal description of the normal gubernacular cone growth is ju dged at least partially responsible for this ignorance. The present st udy therefore describes the normal development of the gubernacular con es in male and female rats from day 14 of fetal life. Androgens are hy pothesized to control male gubernacular cone development but recent ev idence throws doubt upon this proposal. Therefore, the second part of this study describes perinatal development of gubernacular cones in ma le rat foetuses exposed to the anti-androgen flutamide from day 10 aft er conception. Quantitatively normal growth occurred prior to birth, i ndicating no role of androgen in this process. Excessive growth in len gth was noticed during the neonatal period together with delay of gube rnacular cone inversion. These developmental alterations did not repre sent direct anti-androgen-induced modifications of gubernacular cones development as the alterations were not observed in flutamide-exposed neonatally castrated animals. Failure of androgens to affect directly perinatal gubernacular cone growth could represent a rat-specific feat ure. Fetal rabbits show the development of similar structures during t he second half of fetal life. The third part of this study examined th e effect on the development of these structures of exposure of male an d female foetuses to the anti-androgen cyproterone acetate. The latter compound inhibited male internal and external genital development but allowed unaltered gubernacular cone growth. The observations in this report thus present the normal pattern of perinatal gubernacular cone growth in rats together with evidence that these organs show male-spec ific growth independent of androgen. Further work should reveal the te sticular or other factors responsible for this part of male bodily sex ual differentiation processes.