[Age-specific differences in the process of adrenal cortex cell membrane repolarization].

The differences in temperature dependence of the membrane repolarization process (RP) in the cells of zona fasciculata of the adrenal cortex within the range of 7--17 degrees C following preliminary cooling of the adrenal glands to 0 degrees C were investigated in experiments on the isolated adrenal glands of rats aged 5 and 28--29 months. The temperature coefficient (Q10) of RP was much higher in old (2.732 +/- 0.191) than in young rats (1.481 +/- 0.051). Ionol, an inhibitor of free-radical reactions (FRR), did not change Q10 of RP in young animals but decreased it significantly in old ones down to the level of young rats (1.467 +/- 0.028). The total x-raying of young rats (700 Gy) led to an increase in Q10 of RP to 2.515 +/- 0.099 in the first hours after exposure to x-rays. This parameter returned to normal after 48 hours. Age-associated reconstruction of the electrogenic active transport mechanisms is supposed to lie in the appearance (or increased contribution) of FRR in the total balance of reactions determining the active transmembrane transport processes.