Synthesis of insulin-dependent activator of hepatocyte plasmatic membrane Na,K-ATPase decreases in aging.

The experiments on Wistar rats of different age-groups have shown that insulin (1.6 units/kg) provokes hyperpolarization of hepatocyte plasmatic membranes in adult rats, but not in old ones. The hyperpolarization can be prevented by actinomycin D and ouabain, while 2-aminopyridine is ineffective in this case. The appearance of hyperpolarization correlates with the activation of Na,K-ATPase in hepatocyte plasmatic membrane. It is shown that insulin injection provokes the appearance of Na,K-ATPase activation factor in the hepatocyte cytosol. The synthesis of this factor reduces with age.