In vitro analysis of the Na(+)-K+ ATPase activity in neonatal and adult red blood cells.

We studied the role of albuterol in inducing potassium flux mediated by Na(+)-K+ ATPase in neonatal cells under hyperkalemic conditions. Using rubidium as a tracer element, we determined net transmembrane potassium flux in neonatal and adult red blood cells (RBCs) maintained in a buffer solution containing 10 mM KCl. We demonstrated that under these hyperkalemic conditions, albuterol does not increase the net transmembrane potassium flux of the adult RBC. However, neonatal RBCs maintained in these same hyperkalemic conditions demonstrate a significant 50% increase in net transmembrane potassium flux when exposed to albuterol. We conclude the albuterol may be useful in lowering the serum potassium levels in neonates even with extreme hyperkalemia.