Victor Conard

Glucose Metabolism in the Normal Anesthetized Dog Injected Successively with Anti-insulin Serum and Insulin

Seven fasted, healthy, anesthetized dogs were successively injected at a two-hour interval with guinea pig antiinsulin serum and with insulin. The dose of anti-insulin serum used had a total neutralizing potency of 2 U. insulin per kilogram body weight; the amount of insulin used was sufficient to restore normal blood glucose level. Glucose production was determined by hepatic catheterization; glucose tissue utilization by the study of the disappearance rate of a tracer dose of glucose l-C-14. Anti-insulin serum induced hyperglycemia in five dogs and failed to provoke any change in blood glucose among the two others. This difference of behavior was probably related with differing sensitivity to the same fast. In responders, hyperglycemia was accompanied by an increase in liver glucose output and by a reduction of tissue glucose utilization; insulin, when given in sufficient amount to restore normal blood glucose level, induced a decrease of glucose production and an increase in glucose utilization to basal values. In the nonresponders, together with a slight decrease in glucose utilization, a tendency to reduced glucose production was noticed. The doses of insulin necessary to provoke hypoglycemia were three times more important than those used in the responders. The action of insulin on liver glucose production observed in these acute deficiencies of insulin are discussed in relation to experiments previously carried out on normal dogs.

Influence of the intestinal absorption of glucose on the major components of the glycoregulation in anesthetized dogs

The influence of the intestinal absorption of a glucose load perfused during 1 hour in the duodenum of 7 anesthetized dogs has been studied by a complex technic combining the multiple hepatic catheterization, the use of a tracer dose of glucose-C 14 and a bioassay of the insulinlike activity. This method enables one to estimate simultaneously the intestinal absorption of glucose, the transfer to the portal blood, the hepatic storage, the tissue utilization and the changes in the portal serum insulin-like activity. Data concerning the absorption of glucose show that the absorption rate varies from 0.5 to 1.6 Gm./Kg./hr.; the transfer to the portal blood represents 107-57 per cent of the absorbed amount; the yield of the transfer depends on the oxygen consumption by the mesenteric tissues and is approximately in inverse proportion of the increase in blood lactates level. These results come close to that observed in the unanesthetized dog. Following changes in glucose metabolism were observed (1) the hepatic glucose output stops during the absorption period, the liver storing from 20 to 70 per cent of the amount of glucose transferred to the portal blood; (2) the portal serum insulin-like activity shows 2 successive increases: the first and major one at the end of the glucose infusion (mean increase 0.76 mU/ml.), the second one after normalization of glycemia, when the liver resumes its glucose secretion (average 0.35 mU/ml.); (3) the glucose utilization measured by the C 14 disappearance rate is significantly increased during the absorption period. During the absorption period no precise relation is to be found between portal and systemic blood sugar concentrations, the pancreatic response is independent from the blood glucose level, the magnitude of the glucose storage in the liver, mainly due to portal hyperglycemia, is enhanced by the increased serum insulin-like activity.

Effets d'une hyperglycémie prolongée sur le métabolisme glucidique du chien normal

~7~~~~~~~~~~~~~ (1936), ktudiant le chien normal soumis a des perfusions de longue durke, a rythme variable, a dissocie la notion de rendement de l’action de masse proprement dite et a prouvk que, si la captation augmente proportionnellement a la quantitk perfuske, le pourcentage de produit mktabolisi: a la sixikme heure devient de plus en plus faible lorsqu’on augmente le rythme de perfusion, jusqu’i atteindre une valeur basse