Acid glycohydrolase in Chinese hamster with spontaneous diabetes. IV. Diabetes- and line-dependent variation in plasma enzyme activity.

The activity of five glycohydrolases was measured in the plasma of Chinese hamsters from eight highly inbred lines in the Upjohn colony. The diabetic animals showed elevated activities of plasma beta-D-galactosidase, N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase but similar activities of plasma alpha-D-glucosidase and alpha-D-galactosidase to the nondiabetic animals. Line-specific variation was observed in all five enzymes and anomalies were especially evident in N-acetyl-beta-D-glucosaminidase and N-acetyl-beta-D-galactosaminidase activity. In two diabetic lines, AC and Z, activities of these two enzymes were not elevated although significant correlation was found with blood sugar levels. The pronounced difference in the plasma activity of N-acetyl-beta-D-glucosaminidase in two diabetic lines, XA and AC, did not involve plasma inhibitors or activators, as evidenced by the coincidence in observed and calculated activities in mixed plasma samples, or specific isozymes, concluded from the similar elution profiles on ion-exchange column and thermostability curves. These data suggest that diabetes-related changes in plasma glycohydrolase activities are dictated by genetic factors and may be involved in the development of complications.