Changes in the plasmatic membrane characteristics during microsomal monooxygenase induction in the liver of adult and old rats

The experiments on adult (6–8 months) and old (24–26 months) male Wistar rats have shown that treatment of animals with phenobarbital results in a significant increase in hepatic microsomal enzyme content, plasmatic membrane Na +,K +-ATPase activities and the elevation of hepatocyte membrane potential value. It is presumed that the changes in plasmatic membrane characteristics during microsomal monooxygenase induction are related to the synthesis of specific intracellular factors (invertors). This assumption was verified by the experiments with ‘cellular hybrid’ system (cytosol — plasmatic membranes). Using this cross-systems, it was shown that the hepatocyte cytosol of rats treated with phenobarbital produced Na +,K +-ATPase activity. The extent of Na +,K +-ATPase activation was essentially lower when cytosol derived from old rat hepatocytes was used. The presence of specific factors that activated Na +,K +-ATPase in hepatocyte plasmatic membrane was also discovered in blood serum of induced adult and old rats.