Insulin-stimulated glucose uptake, leucine incorporation into protein, and uridine incorporation into RNA in skin fibroblast cultures from patients with diabetes mellitus.

Since intrinsic cellular abnormalities have previously have reported in diabetes mellitus, skin fibroblasts from patients with insulin-dependent diabetes and non-insulin-dependent diabetes, and from age-matched young and old controls, were examined for stimulation by insulin (4--4000 ng/ml) of glucose uptake, leucine incorporation into protein, and uridine incorporation into RNA. No differences in insulin-stimulated glucose uptake were seen between donor types. At 40 and 400 ng/ml, insulin did not stimulate as much leucine incorporation into protein in insulin-dependent diabetics as in young controls (p less than 0.05) and at 4000 ng/ml, less insulin-stimulated leucine incorporation was seen in insulin-dependent diabetics than in young controls or non-insulin dependent diabetics (p less than 0.01). Lower insulin-simulated uridine incorporation into RNA in old controls than in other cell lines appeared to be largely secondary to a two-fold increase in basal incorporation in these old controls. These results provide additional evidence for intrinsic cellular abnormalities in diabetes mellitus. Whether the differences in basal or insulin-stimulated response between fibroblasts of different donor types are attributable to alterations in protein or RNA synthesis, metabolite pool size or turnover have yet to be determined.