Abstract
Na,K-ATPase is the main system effectively excluding the superfluous sodium out of the cells on the expense of energy derived from hydrolysis of ATP. In brain 3 different isoforms of the catalytic α-subunit are known. The present study was focused to energy utilization and ability to bind sodium by the Na,K-ATPase as well as expression of all 3 isoforms of the catalytic α-subunit concerning its sex specificity in two selected regions of the brain, in cortex and in cerebellum of rats. Western blot analysis showed higher expression of all 3 catalytic α-subunits of Na,K-ATPase in cerebellum when compared to cortex which was not followed by higher activity. On contrary the total activity of the enzyme was lower in cerebellum comparing with cortex in females with no significant localization dependent differences of activities in males. Concerning sex dependence only the expression of α3 isoform was higher in cortex of male rats with no differences in the levels of α1 and α2 isoforms. However, the total activity of Na,K-ATPase in cortex was similar in male and female groups. On the other hand in cerebellum of females the total activity of Na,K-ATPase was significantly lower as compared with males. The obtained data indicate localization and sex dependent variations in maintenance of sodium homeostasis in the brain.