125 I-insulin binding to cultured fibroblasts in non-insulin-dependent diabetes in the young.

125 I-insulin binding to circulating monocytes was found to be decreased in Indian patients with non-insulin-dependent diabetes in the young, when compared to controls. To determine whether this was due to an inherent defect in the insulin receptor, fibroblasts from diabetics and controls were grown in an environment free from the diabetic milieu. Under these conditions 125 I-insulin binding to fibroblasts in patients with non-insulin-dependent diabetes in the young was similar to that obtained in controls. (1.5 +/- 0.4% and 1.3 +/- 0.3% per 10(6) cells, p greater than 0.5). It thus appears that the receptor defect manifest on circulating monocytes is unlikely to be a primary defect.