FORMS OF INSULIN-LIKE ACTIVITY AT DIFFERENT SITES OF THE CIRCULATION IN DOGS

ABSTRACT 1. Suppressible serum insulin-like activity (SILA), non-suppressible SILA and the insulin-like activity (ILA) levels of the A (albumin-alpha 1 globulins) and B (beta-gamma globulins) fractions have been quantitated in different sites of the circulation of intact anaesthetized dogs. Higher suppressible SILA was found in the pancreaticoduodenal vein than in the femoral artery. 10 minutes after the intravenous administration of glucose an increase was noted in suppressible SILA in all sites sampled. No difference was detected in non-suppressible SILA in the femoral artery and the pancreaticoduodenal vein and the values in the femoral artery and the femoral vein were found to be equivalent. After the administration of glucose, lower values were found in the portal vein than in a hepatic vein, while in the fasting state the values in these two vessels were not different. The ILA of the A fractions was found to be lower in the femoral vein than in the femoral artery, and after the administration of glucose a tendency to higher values in the pancreaticoduodenal vein than in the femoral artery was noted. 5. After the administration of glucose the ILA of the B fraction was found to be higher in the pancreaticoduodenal vein than in the femoral artery. The investigation suggested that after the administration of glucose, the ILA of the B fraction was lower in the hepatic vein than in the portal vein. 6. Investigation of immunologically determined insulin showed lower values in the femoral vein than in the femoral artery. 7. The ILA of the A and B fractions was not increased after the oxygenation of the venous blood.