EXPRESSION OF A NOVEL SODIUM-HYDROGEN EXCHANGER IN THE GASTROINTESTINAL-TRACT AND KIDNEY

We have recently cloned a novel Na+/H+ exchanger (NHE-2) from rat smal l intestinal cDNA library. The present report characterizes the expres sion of (NHE-2) mRNA in the rat small intestine, stomach, and kidney u sing Northern blot analysis and in situ hybridization techniques. NHE- 2 mRNA was detected in the surface epithelium of the stomach, villus b ut not crypt epithelial cells of the small intestine and in the distal convoluted, but not in the proximal tubules of the kidney, This distr ibution suggests a functional role in the transport of sodium across t he apical membrane of the gastrointestinal tract and the kidney.