EFFECT OF CORTISONE ON GROWTH OF CHICK EMBRYOS DURING EARLY EMBRYOGENESIS1

Abstract

Cortisone acetate was administered on the initial day of incubation and at two or three day intervals thereafter to Cornish cross-White Hampshire chick embryos. The weight and length measurements were compared with controls on the fourth, seventh and tenth incubation days. A growth retarding effect of cortisone was demonstrated, which was more strikingly manifested in the alteration of the average length of the embryo in the earliest period, and in the alteration in average weight in the later periods. With this demonstration of growth retardation as early as the fourth day of incubation, it would appear unlikely that this effect is due to a suppression of somatotropin secretion by the hypophysis, since the latter is not fully differentiated prior to the tenth day. It would appear more likely that this effect represents a direct inhibition of protein synthesis and growth by cortisone.