[Modulation of Na+,K+-pump activity and Na+,Li+-exchange in rabbit erythrocytes at various stages of cholesterol feeding].

The activities of the Na+,K(+)-pump and the Na+/Li(+)-exchange and the intracellular concentration of Na+ in erythrocytes of rabbits with experimental hypercholesterolemia have been studied at different stages of cholesterol (Ch) feeding as well as at different intervals after stopping of cholesterol-rich diets. After sufficiently long periods of feeding the animals with Ch (1.5-2 months), a significant activation of the Na+,K(+)-pump, reduction of the Na+/Li(+)-exchange rate and lowering of the intracellular sodium content in erythrocytes of rabbits from experimental groups were observed. Several months after stopping Ch-rich diets there was a partial normalization of the parameters under study. However, at the initial stage of the experiment (20 days after the beginning of Ch feeding) as well as two weeks after Ch feeding had been stopped, there occurred no changes in the activities of the ion transport systems or in [Na+]i despite substantial changes in the plasma Ch level. It is suggested that the observed effect of dietary Ch on the activity of ion carriers may be mediated by affecting the expression of the corresponding genes.