Influence of Hyperinsulinemia and Insulin Resistance on In Vivo beta-Cell Function Their Role in Human beta-Cell Dysfunction

OBJECTIVE-Recent work has shown that insulin stimulates its own secretion in insulin-sensitive humans, suggesting that insulin resistance in the beta-cell could cause beta-cell dysfunction. We have tested whether insulin exposure and insulin sensitivity modulate beta-cell function in subjects with normal glucose tolerance (NGT) and whether they contribute to dysglycemia in impaired glucose regulation (IGR).