THE EFFECT OF GROWTH HORMONE ON THE NUCLEIC ACID CONTENT OF THE DEVELOPING CHICK EMBRYO1

Abstract

Anumber of investigators (Collip, 1934; Lee, 1936; Evans et al., 1948; Whitney et al., 1948; have observed an increase in body weight of young (sexually immature) animals receiving hypophyseal growth hormone. Similarly, growth hormone given to adult rats results in an increase in the size of all organs, but of muscles particularly (Greenbaum and Young, 1950). Recently, Hsieh et al. (1952), have likewise observed an increase in body weight of newly hatched chicks which had received growth hormone during embryonal development. As Russell (1953) has pointed out, it seems most likely that at least part of the action of this hormone is on some phase of the synthesis of amino acids into protein. The investigations of Brachet (1941, 1950) and of Caspersson (1941) have shown that when there is a state of active protein synthesis, a marked accumulation of pentosenucleic acid (PNA) occurs in all cells. That growth hormone may increase nucleic acid synthesis is indicated by the investigations of DiStefano et al.