Evidence suggesting renal tubular excretion of potassium in man during recovery from acute renal insufficiency.

In 1942 Winkler and Smith (1), studying the simultaneous renal clearances of exogenous creatinine and potassium in dogs following the injection of potassium salts, concluded that potassium is normally filtered at the glomerulus and subjected to a variable degree of tubular reabsorption. The highest potassium/creatinine clearance ratio obtained by these authors was 0.40. In 1948 Berliner and Kennedy (2), and Mudge, Foulks and Gilman (3) independently and simultaneously published convincing evidence for active renal tubular excretion4 of potassium in the dog. The former authors obtained potassium/creatinine clearance ratios as high as 1.33 in trained dogs receiving oral potassium chloride for one week before the experiment, and hypertonic solutions of this substance intravenously during the experiment. The latter investigators obtained potassium/creatinine clearance ratios as high as 1.39 in anesthetized dogs receiving intravenous potassium chloride during urea-induced osmotic diuresis. McCance and Widdowson (4) in 1937 were the first to suggest the possibility of tubular excretion of potassium in man. They observed an isolated potassium/inulin clearance ratio of 1.24 in a man suffering from acute alkalosis at a time when his inulin clearance was depressed to 9.3 ml./min. In 1943 Keith, King and, Osterberg (5) stated that they observed