Changes of insulin and glucagon binding to receptors in hepatocytes during liver regeneration.

ABSTRACT

The binding of insulin (INS) and glucagon (GL) on isolated rat hepatocytes during the process of liver regeneration after partial hepatectomy was determined. Adult male rats were subjected to 65-70% partial hepatectomy, control animals were sham-operated. The binding of radioiodine 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 and microviscosity of liver plasma membranes were also measured. The decrease of INS receptor binding capacity was found 1, 2, and 3 days after operation. No differences in sham and partially hepatectomized groups in INS binding were noted 5 days after operation. A single insulin injection during the process of regeneration did not affect these changes of INS binding to hepatocytes. The increase of GL binding was observed on the third day after partial hepatectomy, however, on the 5th day no changes of GL binding to its receptors were noted. The plasma insulin and glucose levels were similar in both hepatectomized and sham-operated rats. The increase of plasma membrane microviscosity of hepatocytes during the process of liver regeneration and a negative correlation 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.