Potentiation of insulin action: a probable mechanism for the anti-diabetic action of sulfonylurea drugs.

Insulin action was assessed by measuring insulin-mediated glucose disposal (KI) in 13 non-ketotic diabetic patients both before treatment and after normalization of plasma glucose by diet (5 patients) or sulfonylurea (glipizide) therapy (8 patients). While the KI of the diet-treated group was unchanged by therapy, that of the glipizide-treated group was significantly increased. The data show that chronic glipizide therapy is associated with a potentiation of insulin action, which may account for the major anti-diabetic effect of this drug.