Abstract
The activities of adenylate kinase (ATP:AMP phosphotransferase, EC 2.7.4.3) in lyophilized cryostat sections of various organs from mice with the obese-hyperglycemic syndrome (gene symbol ob/ob) were measured fluorometrically. Skeletal and heart muscle tissues had the highest enzyme activities, i.e. 258 and 155 mmoles substrate converted per kg dry weight and per hr (MKH), respectively. Pancreatic islet specimens, which were composed mainly of B-cells, possessed the highest activitty of all parenchymatous cells studied, with 18 MKH as compared to 16 MKH for the cortical tubules of the kidney and 7 and 6 for the exocrine pancreas and liver cells, respectively. The granular layer of the cerebellum had enzyme activity of 31 MKH. The adenylate kinase activity in the B-cells was apparently not influenced by hyperglycemia since it was similar both in obese-hyperglycemic mice of different ages and in lean mice, although the blood sugar concentrations in such animals are much different.