Regulation of H and K transport in renal tubules

Abstract

Summary of Project.The presente Project involves transfer mechanisms of H+ and K+ across renal epithelium and their regulation. Transport of potassium, e major ion responsible for regulation and maintenance of cellular and luminal concentrations, will be studied, particularly from the point of view of proximal reabsorption, thought to be mainly passive via the paracellular path, but that may be regulated by agents such as the intercellular proteins such as claudins and physiological or pharmacological levels of ouabain. We will be able to observe rates of transepithelial transfer of potassium by changes in luminal K concentration after injection of high K solutions using microelectodes. This process will be also investigated during hypokalemia, e.g. measuring changes in claudin expression via western blot of proximal epithelum proteins. Regulation of proximal H+ secretion (Na+ reabsorption by NHE3) dependent of the renin angiotensin system will be investigated using recently discovered agents such as alamandin, making use also of microperfusion methods develloped in our laboratory. (AU)