Abstract

The phosphorylase activity and glycogen content in mammary carcinoma transplants in fasted C57BL mice, in hepatoma transplants in fasted Wistar rats, in the livers of these tumor-bearing animals, and in the livers of fasted controls were investigated. In both the mouse mammary tumor and the rat hepatoma the phosphorylase was relatively inactive without the addition of adenylic acid. With added adenylic acid no significant difference was found between the phosphorylase activity in the tumors, the livers of the tumor-bearing animals, and the livers of the controls. The glycogen values were low in both tumors tested. An apparent but not highly significant reduction in phosphorylase activity (without added adenylic acid) and glycogen content was also observed in the livers of the tumor-bearing animals. It is suggested that the diversion of glucose entering the tumor cell from the metabolic pathway leading to glycogen synthesis may be attributed in part at least to a low activity of the phosphorylase system. The possibility of the utilization of adenylic acid for other synthetic functions in the tumor cell and the consequent loss of this activator to the phosphorylase system is discussed. * Fellow of the National Cancer Institute of Canada.