My laboratory is focused on studying the regulation of Na+ and K+ transport in aldosterone-sensitive distal tubules of the kidney. Na+ is a major extracellular ion and plays a key role in maintaining extracellular volume, and decreasing extracellular Na+ content can result in hypotension whereas increasing Na+ content causes hypertension. Conversely, K+ is mainly located in the intracellular fluid and extracellular K+ must be maintained in a narrow range: either high plasma K+ (hyperkalemia) or low plasma K+ (hypokalemia) can cause life-threatening cardiac arrhythmias. The kidney plays a key role in secreting K+ to match the dietary K+ intake, and disorders of K+ balance are common in patients with kidney failure.