Insulin receptors in myotonic dystrophy: a study with mononuclear leucocytes and erythrocytes.

We evaluated insulin receptor activity on mononuclear leucocytes and erythrocytes in 9 patients with myotonic dystrophy and in 9 controls. The results demonstrated that in myotonic dystrophy: 1. insulin binding to specific receptors was significantly impaired (P less than 0.01) because of a reduction in the number of high and low affinity receptors. 2. the affinity constants were not significantly affected 3. there was no correlation between receptor activity, insulin behaviour and glucose tolerance. These data obtained in two different cellular systems suggest that the constant numerical reduction of insulin receptors was probably due to a systemic membrane defect, typical of myotonic dystrophy.