- V V Frolkis: Institut of Gerontoloy Academy of Medical Sciences of Ukraine, Kiev, Ukraine.
Effect of insulin on Na, K-ATPase activity and phospholipid (PL) composition of myocardiocytes' plasma membrane (PM) was investigated in adult (6 months old) and old (28 months old) male Wistar rats. Administration of insulin increases Na, K-ATPase activity and phosphatidilethanolamin content, and decreases phosphatidilinositol content of myocardiocytes' PM in adult animals. Administration of insulin doesn't change Na, K-ATPase activity and decreases phosphatidilethanolamin content of myocardiocytes' PM in old rats. In the experiments with cellular hybrids (cytosol + PM) it was found that cytosol of adult insulin-treated animals caused the activation of Na, K-ATPase in both adult and old rats. Cytosol of old animals did not influence enzyme activity either in old or adult animals. Actinomycin D inhibited a stimulating insulin effect on Na, K-ATPase activity. The obtained data may suggest the presence of insulin-induced synthesis of intracellular factors responsible for resultion of the state of PM invertors.