Insulin binding to liver plasm membranes in the obese hyperglycemic (ob/ob) mouse. Demonstration of a decreased number of functionally normal receptors

Abstract

In previous studies, the insulin resistance of the obese hyperglycemic mouse (ob/ob) was found to be associated with decreased insulin binding to liver, fat, and lymphocytes. The present study demonstrates that the insulin receptors in the liver membranes of the ob/ob mouse are decreased in number, but are indistinguishable from normal by other criteria including affinity, kinetics of association and dissociation, temperature dependence of binding, and biological specificity of the binding reaction. The receptor in liver membranes of the ob/ob mouse is also indistinguishable with respect to insulin receptor site-site interactions. Degradation of both insulin and of receptor sites was studied and did not account for differences observed in binding. We conclude that the insulin receptor from the ob/ob mouse is a functionally normal receptor and that its presence in diminished number accounts for the observed decrease in insulin binding to liver plasma membranes.