Histochemical demonstration of phosphorylase and UDPG-glycogen transferase in fertilized and unfertilized mammalian eggs.

In mammalian eggs, glycogen may well play an important role as an energy source during cleavage. Although the presence of glycogen in rat and rabbit eggs and the fluctuation of its concentration during development have been reported (ISHIDA 1954, 1963), histochemical demonstration of enzymes related to glycogen metabolism has not yet been published. Studies of glycogen metabolism are generally based on the concept that the glycogen-synthesizing enzymes are pyrophosphorylase and uridine diphosphate glucose (UDPG)-glycogen transferase and that phosphorylase is the enzyme which is responsible for glycogen breakdown and further that branching and debranching enzymes are present in the metabolic pathway of glycogen (cf. STETTEN and STETTEN 1960). Since TAKEUCHI and KURIAKI (1955) have set their steps in the field of histochemical demonstration of phosphorylase in animal tissues, reliable new information concernina enzymes responsible for glycogen metabolism as just stated have been brought about by some investigators (TAKEUCHI 1956, 1958; TAKEUCHI and KURIAKI 1955; TAKEUCHI, HIGASHI and WATANUKI 1955; TAKEUCHI and GLENNER 1960, 1961 a, b; GOLDBERG, WADE and JONES 1952; GUHA 1961; GUHA and WEGMANN 1959, 1960; WEGMANN and GUHA 1959; VERNE, WEGMANN and GUHA 1959; GRILLO 1960, 1961; ERANKO and PALKAMA 1961; GODLEWSKI 1960, 1962, 1963). The present paper deals with the histochemical demonstration of phosphorylase and UDPG-glycogen transferase in hamster eggs during their loss of fertilizability, and of the same enzymes in hamster and rabbit eggs before and after fertilization, and at early stages of development prior to implantation.