Decreased autophosphorylation and kinase activity of insulin receptors in diabetic Chinese hamsters.

To clarify the role of the insulin receptor in diabetes, the hepatic insulin receptor was investigated in the spontaneously diabetic Chinese hamsters, which are the animal models for insulin-deficient diabetes. Insulin binding in the diabetic animals increased mainly due to an increase in the number of receptors. It was also observed that both the autophosphorylation and kinase activity of the hepatic insulin receptor were decreased in the diabetic animals compared to the control animals. These changes in the hepatic insulin receptor may be caused by the diabetes itself. As the phosphorylated protein of 95 kDa was immunoprecipitated by the anti-insulin receptor antibody (B-10, human) in both diabetics and controls, it was supposed that the 95 kDa protein would be the beta-subunit of insulin receptors, as in other animals. These animals seem to be useful for examining insulin receptors in diabetes.