Increased Liver Phosphatase Activity in Alloxan-diabetic

Contributions from Cori’s laboratory by Colowick et al. (3, 4) and Sutherland (5) have proposed the concept that the effects of certain hormones (from the anterior pituitary, adrenal cortex, and pancreas) in carbohydrate metabolism are iinked with their action on specific tissue enzymes. The action of insulin as thus far uncovered by the above investigators is not simple, and involves in skeletal muscle the removal of inhibitions t,o the activity of hexokinase (3, 4), while in liver glycogenesis may be stimulated, presumably through an increase in phosphorylase activity (5). It seems probable that insulin may have still other points of action (3). The present investigation of another of the enzymes prominently involved in carbohydrate metabolism, a study of liver phosphatases in an experimental diabetic state, was encouraged by (1) our findings (6) that alimentary hyperglycemia in rats induces increases in the activities of the acid and alkaline phosphatases of the kidney, and that an in vitro inhibition of phosphorylation in kidney homogenates may be produced by the addition of phosphatase, and (2) the report of Thannhauser and his colleagues (7) that in glycogen disease the alkaline phosphatase activity of the liver is diminished. The work has disclosed that in a well established alloxan-diabet,ic state in rats the activities of both acid and alkaline liver phosphatases are significantly increased. Furthermore, our experiments suggest that in such alloxan-diabetic animals, treated effectively with insulin, there is a return towards normal levels of liver phosphatase activity.