Abstract
A longitudal study was carried out to separate the effects of treatment with diet from those of treatment with glibenclamide and phenformin on the oral glucose tolerance test (OGTT) plasma sugar and insulin levels in 118 patients with maturity-onset diabetes mellitus. Both drugs improved glucose tolerance and random blood sugar levels more than diet alone. The improved glucose tolerance with both drugs was due to a combination of a reduced fasting plasma sugar level and an improved tolerance to the glucose load. Treatment with glibenclamide increased insulin secretion but phenformin had no significant effect. Mean body weight fell slightly during phenformin administration, whereas a small but insignificant rise in patients receiving glibenclamide.