CHANGES OF INSULIN AND GLUCAGON BINDING TO RECEPTORS IN HEPATOCYTES DURING LIVER-REGENERATION

The binding of insulin (INS) and glucagon (GL) on isolated rat hepatoc ytes during the process of liver regeneration after partial hepatectom y was determined. Adult male rats were subjected to 65-70 % partial he patectomy, control animals were sham-operated. The binding of radioiod ine labelled INS and GL to isolated hepatocytes was determined 1, 2, 3 and 5 days after the surgery. The plasma levels of INS and glucose an d microviscosity of liver plasma membranes were also measured. The dec rease of INS receptor binding capacity was found 1, 2, and 3 days afte r operation. No differences in sham and partially hepatectomized group s in INS binding were noted 5 days after operation. A single insulin i njection during the process of regeneration did not affect these chang es of INS binding to hepatocytes. The increase of GL binding was obser ved on the third day after partial hepatectomy, however, on the 5th da y no changes of GL binding to its receptors were noted. The plasma ins ulin and glucose levels were similar in both hepatectomized and sham-o perated rats. The increase of plasma membrane microviscosity of hepato cytes during the process of liver regeneration and a negative correlat ion between INS binding and membrane microviscosity were found. These results demonstrated significant changes in binding parameters of both INS and GL receptors in hepatocytes during liver regeneration induced by partial hepatectomy.