The insulin receptor in myotonic dystrophy.

Insulin binding was studied using circulating monocytes obtained from seven patients with myotonic dystrophy and seven control subjects. During an oral glucose tolerance test the 2 h plasma glucose value was significantly higher in patients with myotonic dystrophy compared to controls, and 5 out of the 7 patients demonstrated hyperinsulinemia. This combination of abnormal glucose tolerance and hyperinsulinemia suggests insulin resistance. There was no difference in insulin binding to monocyte receptors between the two groups. These results suggest that no abnormality exists in the insulin receptor in myotonic dystrophy.