THE EFFECTS OF VARIATIONS IN WATER OR POTASSIUM INTAKE ON THE RENAL EXCRETION OF POTASSIUM IN SHEEP

Abstract

By infusing water into the rumen of sheep receiving a fixed potassium intake the relationship between excretion of potassium and urine volume was examined. Both the osmotic pressure and the concentration of potassium in the urine fell as the urine volume was increased, but the amount of potassium excreted was not affected by urine volume provided this was above 1·0 to 1·5 1./day. When the potassium intake of sheep was increased through the range 236–1186 m.equiv./day there was a proportional increase in the amount of potassium excreted in the urine. Between 236 to 889 m.equiv./day there was no change in the amount of potassium filtered across the glomerulus, but above this the amount of potassium filtered across the glomerulus increased. This result suggests that when potassium intake is very high a proportion of the potassium filtered across the glomerulus may augment the secretory process in eliminating dietary potassium excesses. © 1969 The Physiological Society