Increased activity of some enzymes in serum in cases of severely decompensated diabetes, with and without ketoacidosis.

In each of 10 highly hyperglycemic decompensated diabetics with ketoacidosis, we found a markedly increased serum activity of two lysosomal hydrolases (N-acetyl--glucosaminidase and -glucuronidase). This was also true to a lesser degree of five diabetics with less severe decompensation and without ketoacidosis. The activity of both enzymes and the degree of hyperglycemia were highly correlated. We think these enzymatic changes result from a process of activation and release of tissue lysosomal enzymes, probably occurring in connection with the increased catabolism present in decompensated diabetes. Nonlysosomal (cytoplasmic or mitochondrial) enzymes were less changed (aspartate and alanine aminotransferases) or normal (aldolase, lactateand malate dehydrogenase, and creatine kinase). This indicates that tissue damage alone could not account for the increased activity of the two lysosomal hyd rolases; it therefore seems primarily to be due to involvement of lysosomes.