Rapid Rate of Turnover of Potassium Ions in Kidney Slices

Abstract

THE steady-state turnover-rate of potassium ions in guinea pig cortex slices in vitro was measured by the isotope procedure developed by Krebs, Eggleston and Terner¹. There is a rapid initial loss of potassium when kidney slices are placed in physiological saline solutions, but if 0.01 M α-ketoglutarate is present, the slices reabsorb the lost potassium¹ and maintain the initial concentration during at least the interval from 25 to 35 min. after the start of the incubation. When this steady state had been reached, potassium-42 chloride was added to the medium and the tissue removed either two or four minutes later. Measurements were then made of the radioactivity and the potassium content of tissue and medium with a liquid counter² and a flame photometer³. Typical results are shown in the accompanying table.