THE ROLE OF INVERTORS (INTRACELLULAR ACTIVATORS) IN AGE-RELATED-CHANGES IN CELL RESPONSE TO HORMONES

It has been shown that a number of hormones (insulin, testosterone, thyroxine, and adrenaline) can stimulate synthesis of plasma membrane regulators-''inventors'' in a cell. The synthesis of ''invertors,'' which is under genomic control, decreases with age. As a result, insulin, testosterone, and thyroxine do not provoke Na,K-ATPase activation and plasma membrane hyperpolarization of hepatocytes and myocardiocytes in old rats. Also, due to desensitization of the heart to adrenaline, a smaller decrease occurs in adenylate cyclase activity in old animals. The Na,K-ATPase of plasma membranes of old animals maintain their ability to respond to the ''invertors.'' The decrease in the synthesis of ''invertors'' represents an important mechanism of change in the cell's reaction to hormones.