Improvement of glucose tolerance by minimal doses of glipizide in obese subjects with different degrees of glucose intolerance.

Obesity and impaired glucose tolerance (IGT) are risk factors for non insulin dependent diabetes mellitus (NIDDM) and for ischemic heart disease. Long term treatment of IGT subjects with diet and tolbutamide prevents progression of IGT to NIDDM. We have evaluated the lowest dose of glipizide, a second-generation sulfonylurea, able to improve glucose tolerance in response to oral glucose in 31 obese subjects, 12 with NIDDM, 9 with IGT and 10 with normal glucose tolerance (NGT). All subjects underwent four OGTTs, preceded by placebo and by different doses of glipizide (0.5, 1.0, 2.5 mg). Glucose tolerance was progressively improved by increasing glipizide doses in all groups, probably by peripheral mechanism and by enhanced insulin release.