Studies on the Oxidative Metabolism of the Chick Embryo

IN PREVIOUS reports of studies on embryonic metabolism carried out in this laboratory (Feldman et al., 1958; Feldman and Couch, 1960) a system was defined for the stimulation of oxygen uptake of chick embryo preparations. It was pointed out that the maximal oxidative rate required a balance between the breakdown of adenosine triphosphate (ATP) and its synthesis. Furthermore, it was found that oxygen uptake by chick embryo preparations proceeded slowly unless magnesium and ATP were added in vitro. The addition of low concentrations of dinitrophenol in vitro stimulated the oxygen consumption of cell-free extracts of 10-day chick embryos (Feldman et al., 1958). The stimulatory effect of dinitrophenol was also observed with cell-free extracts of embryos which had been removed from eggs injected with the drug. Very little is known of the enzymatic activity of older chick embryos, particularly the enzyme systems involved in energy metabolism. It was felt that a …