Bernice Friedmann

Action of Insulin and Tolbutamide on Blood Glucose Entry and Removal

Although it is generally recognized that the blood sugar of the fasting animal is maintained constant by a precise balance between entry and removal rates, it is only recently, with the advent of C-labeled glucose, that reliable estimations of the rates of these processes have become possible. The availability of tracer methods has also greatly facilitated studies of the mechanism of action of agents which affect the blood sugar level. Such studies, by Searle and Chaikoff, Henderson et al., Wall et al., Berson et al., and Dunn et al. have shed considerable light on the relationships between blood glucose level and its entry and removal rates, and the effects thereon of various hormones. In our own studies, we have been struck by the marked and immediate action of insulin in suppressing the entry of new glucose into the blood of the fasting, normal dog. As a further step in the investigation of this presumably hepatic action of insulin, its effect on the normal and diabetic human has been studied, and its action on the entry and removal rates of blood glucose has been compared with that of the hypoglycemic drug, tolbutamide (Orinase).* These studies are described in the present report.