ACTIVITIES OF VARIOUS AMINOTRANSFERASES IN TUMOR-BEARING RATS.

Abstract

This communication reports changes in the activities of tyrosine aminotransferase (EC 2.6.1.5,[1][1] l-tyrosine:2-oxoglutarate aminotransferase), alanine aminotransferase (EC 2.6.1.2, l-alanine:2-oxoglutarate aminotransferase), and aspartate aminotransferase (EC 2.6.1.1, l-aspartate:2-oxoglutarate aminotransferase) in tumor-bearing rats. From the results and studies on various analogous conditions, the metabolism of tumor-bearing animals is discussed. It was found that the activities of aminotransferases of liver cell sap show a biphasic change—first decreasing and then increasing during the tumor-bearing process—and that the raised activities are reduced before death. It is suggested from our studies that, although there seems to be a continued internal protein deficiency (hypoproteinosis) from an early stage of tumor bearing, there is a hyperfunction of the hypophyseal-adrenal cortical system, perhaps induced by the increased internal utilization of glucose (by the tumor) in the advanced stage, and a sudden decrease in adrenal function prior to death of the animal. [1]: #fn-2