Effect of insulin on the proline transport activity in cultured fibroblasts from patients with Werner syndrome.

The effect of insulin on the transport of proline has been studied in cultured fibroblasts from normal individuals, non-insulin-dependent diabetic patients, and patients with Werner syndrome. In fibroblasts from normal individuals and those with diabetes mellitus, incubation with 10(-7) M insulin resulted in more than a twofold increase in the transport rate after about 14 h incubation. In contrast, fibroblasts from patients with Werner syndrome had a markedly attenuated response to insulin, suggesting a defect in insulin action on the transport of this amino acid in Werner syndrome.