Measurements of the Enzymatic Activities Required for ATP Formation by Glycolysis in the Pancreatic Islets of Hyperglycemic Mice (NZO)

Metabolic studies with 1-C-14 and 6-C-14 glucose have led to the assumption that the glycolytic degradation of glucose is of minor importance in the islets. In the present investigation the enzymatic activities of phosphoglyceric kinase and pyruvic kinase are measured in the pancreatic islets and acini, since these enzymes are required for the glycolytic formation of ATP. The activities are obviously high and significantly highest in the islets. The enzymes linked to the conversion between NAD and NADH show much lower activities. In accordance with the general conception of the pacemakers in the anaerobic breakdown of glucose, glyceraldehyde-3-phosphate dehydrogenase may be assumed io be rate limiting for the glycolytic formation of ATP. This possibility is discussed with reference to the low activity of phosphofructokinase found in the islets.