The Diabetogenic and Growth-Promoting Activities of Growth Hormone (Somatotropin) in the Developing Chick Embryo

THE experiments reported here were designed to determine whether or not growth hormone normally produced by adult mammals influences embryonal growth. Fetal gigantism occurring in human diabetic or potentially diabetic mothers (Krist and Futcher, 1948) has been suggested as due to excessive maternal growth hormone production. Several investigators have demonstrated a diabetogenic effect of growth hormone in intact (Cotes et al., 1949; Campbell et al., 1950; and Milman and De Moor, 1950) as well as partially depancreatectomized adult mammals (Milman and Russell, 1949, and Houssay and Anderson, 1949). However, such a response could not be elicited in growing puppies and kittens (Young, 1941, 1944, 1949), or in pregnant or lactating cats and dogs (Young, 1938, 1946). Evans, Simpson and Li (1948) have reported that growth hormone produces a continuous growth in normal adult female rats. Recently, Reid (1952) has shown that the ratio of diabetogenic to growth-promoting activity is approximately a constant, thus suggesting that the two activities may be attributed to the same structure in the same protein molecule.