THE MECHANISM OF POTASSIUM EXCRETION IN THE CHICKEN

Abstract

Excretion of K and H ions was examined in the chicken using the method of Sperber. Unilateral changes were interpreted as indicative of tubular effects. Secretion of K into urine is inversely related to that of H ion. Alterations in the secretory rates of K and H ions are mediated by changes in the peritubular (and/or the renal intracellular) concentrations of these ions and are not necessarily related to changes in systemic acid-base balance. The secretory mechanism for K may be saturated, is subject to competitive inhibition, and is interfered with in a reversible fashion by Hg, a pharmacologic inhibitor. Data indicate that linked transfer of K, H and Na ions is probably accomplished by a carrier mechanism. Association and dissocaition of the hypothetical cation-carrier complex is apparently rate-limiting in the tranaport process. Preferential association of either K or H ions with the carrier may be a function of the relative preponderance of one or the other ion within the tubule cell.