Studies on the Metabolism of Glucagon-I131in Rats1

THE lack of pure preparations of glucagon has impeded studies of its metabolism in the past. As the result of recent investigations, glucagon has been isolated in crystalline form (1), and its structure has been clarified (2). The ability to radioiodinate glucagon without loss of biological activity has facilitated the study of the metabolism of the compound. This paper describes experiments designed to elucidate the distribution and degradation of glucagon-I131 and its excretion in urine and feces following administration of the material into the caudal vein of rats. The distribution and degradation of glucagon-I131 following its injection into the portal vein have also been compared with its fate after injection into the inferior vena cava.