Determination of Rates of Glucose Oxidation in Normal and Diabetic Dogs by a Technique Involving Continuous Injection of C¹⁴-Glucose

¹ From the Department of Physiology, University of California School of Medicine, Berkeley, California

A procedure involving the continuous intravenous injection of C¹⁴-labeled glucose for measuring the rates of glucose oxidation and turnover in the dog is described. The total amount of labeled glucose administered during 6 hours need not exceed 0.1 mg, an amount quite negligible with respect to the size of the glucose pool in the dog and, consequently, too small to disturb the steady state of endogenous glucose metabolism. The advantage of this procedure lies in the fact that the calculations made are free of assumptions required in the single-injection method. As determined by the continuous-injection method, the normal dog oxidizes glucose at a rate of about 100 mg/kg/hr., and the diabetic dog (completely depancreatized) oxidizes glucose at a rate of about 50 mg/kg/hr. The injection of insulin in the diabetic dog restores the rates of glucose oxidation to near normal. A discussion is presented on the validity of the single-injection procedure for determination of rates of glucose oxidation in animals.