Cellular potassium transport and ATPase activity in Bartter's syndrome.

The cellular membrane function expressed as ATPase activity and active cellular K+ changes during in vitro incubation has been studied in two siblings with Bartter's syndrome. The K+ content of skeletal muscle was 20% lower than for controls, and the active potassium transport ability of single skeletal muscle cells was also lower than that of controls. The total ATPase activity of red cell membranes was higher, but the ratio of Na+-K+-activated to Mg2+-activated ATPases was lower than for control patients. The results favour the hypothesis that a primary defect causing the Bartter's syndrome could be an inherited generalized membrane dysfunction in the handling of cations.