Gliclazide on long-term therapy increases insulin response to glucose of type II diabetics.

Twelve type II diabetics were treated with gliclazide, a potent hypoglycaemic sulfonylurea, for 5 months. Plasma immunoreactive insulin (IRI), connecting peptide (C-peptide) and immunoreactive glucagon (IRG) were measured during a 2 h oral glucose tolerance test (OGTT) before and during gliclazide therapy. The OGTT improved in 7 patients. In those patients IRI concentrations were significantly more elevated during than before the treatment period. By contrast, gliclazide treatment did not affect the hepatic extraction of insulin (estimated by the molar ratio of C-peptide to IRI) nor the inappropriate glucagon release commonly observed in this type of patients.