[Effect of short-term experimental hyperinsulinemia on insulin binding and glucose oxidation in adipocytes]

To investigate the effect of hyperinsulinemia on insulin action in target cells, insulin binding to adipocyte membranes and glucose oxidation in adipose cells were measured in control and experimentally hyperinsulinemic rats. The results showed that: 1) body weight, food intake and adipocyte diameter were not significantly changed, but serum insulin was significantly increased and blood glucose was markedly decreased in hyperinsulinemic rats as compared to control; 2) adipocyte membranes from hyperinsulinemic rats bound significantly less insulin than those from control rats, with a decreased number of insulin receptors and unchanged affinity of receptors for insulin; 3) significantly increased basal (in absence of added insulin) and insulin stimulated glucose oxidation was found in hyperinsulinemic rats as compared with control. The data suggest that experimental hyperinsulinemia resulted in decreased numbers of insulin receptors but increased responsiveness to insulin in target cells.