Na super(+)-K super(+)-ATPase pump function in rat brain synaptosomes is different in males and females

To understand the increased morbidity and mortality associated with acute hyponatremia in young women, the authors characterized the Na super(+)-K super(+)-adenosinetri-phosphatase (ATPase) pump in rat brain synaptosomes to determine if this adaptive mechanism was different between the sexes. Veratridine-stimulated sodium (Na super(+)) uptake was significantly greater in females than in males, suggesting either an increased rate of Na super(+) uptake and/or decreased extrusion of Na super(+) by the Na super(+)-K super(+)-ATPase pump in females. Transport evaluation of the Na super(+)-K super(+)-ATPase pump showed ouabain-sensitive K super(+) uptake in males to be significantly greater than in females and ouabain-sensitive Na super(+) uptake in inverted synaptosomes was 70% greater in males.