GONADAL AND HYPOPHYSEAL INTERACTIONS ON THE CHONDROGENESIS IN YOUNG FOWL

Abstract

The proliferating zone in the epiphyseal cartilage of the long bones in birds produced by estrogens may be in an indirect effect mediated by the pituitary. Both growth hormone and prolactin were injected simultaneously with estradiol benzoate. Only prolactin was active, markedly counteracting the inhibition of the estrogen on cartilage proliferation. The hypothesis is advanced that in birds prolactin assumes the function of growth hormone in mammals.