Development of interstitial cells in experimentally sex-reversed gonads of genetically female chick embryos.

A testis graft implanted in young genetically female embryos induced a male gonadal differentiation. The interstitial cell percentage and actual content were strongly lowered in masculinized gonads compared to normal female embryos and became similar to those observed in the normal developing embryonic testis. This effect was enhanced by the association of a graft and an antiestrogenic drug, and was not observed after administration of the drug alone. This inhibiting influence of the graft on interstitial cell formation may be considered as resulting in an inhibition of estrogen production. Its possible causative role in gonadal masculinization is discussed in the light of previous and present results.