Studies on Glycolysis during the Early Development of the Rana pipiens Embryo

Abstract

A study of the anaerobic glycolytic metabolism of the Rana pipiens embryo, prior to neurulation, was made. Intact embryos and homogenates were studied. These embryos, which have endogenous glycogen and no free glucose, exhibit a pronounced Pasteur effect. Homogenates contained active enzymes for converting glycogen or the phosphorylated Embeen-Meyerhof intermediates to lactate, but glucose was an inactive substrate. A homogenate requirement for DPN and magnesium ion was demonstrated. All sugars save hexose-di-phosphate require ATP. Fluoride inhibits lactae formation. The enzymes are in the supernatant after high speed centrifugation. Theories to account for the phenomenon of glycogen disappearance after gastrulation were reevaluated and it was concluded that the extent of O2 uptake and lactate appearance fail to account for the extent of disappearance reported.