[Effect of tolbutamide on the activity of transglutaminase]

Five obese patients were studied during 7 days, 750 mg of tolbutamide, per os, was given. Blood samples were drawn at basal state and at 3, 5, 7 days during the treatment and 6 days after it. The values of transglutaminase activity (that in the basal state were similar to that in the controls) decreased significantly at the seventh day of treatment (72.3%). This decrease was transient and rapidly returned to the basal values when the drug was suspended. The results suggest that sulfonylureas exert in part their hypoglucemic effect by modificating the insulin receptor binding through the inhibition of transglutaminase activity.