Possible inter-relations between acidosis and creatine elimination

Abstract

Current views associate the elimination of creatine with some perversion of carbohydrate metabolism. The probability of a close relationship of this sort is indicated by the well known fact that a deficiency of carbohydrate in the body leads to creatine elimination which may be checked promptly by ingestion of carbohydrate. There are experimental facts which the familiar hypothesis fails to explain. McCollum and Steenbock 1 found that in the pig a diet of corn products led to the appearance of relatively large quantities of creatine in the urine. Similar experiments of Folin (reported at the December meeting of the American Society of Biological Chemists) with oat feeding yielded comparable results. The dietaries employed can scarcely be regarded as lacking in carbohydrate.

Deficiency of carbohydrate usually means an accompanying acidosis, not necessarily caused by ketogenic substances, which presumably involve the tissues associated with creatine-creatinine metabolism. At any rate nearly every instance in which there is creatine in the urine is accompanied by an acidosis—generally a ketonuria also. These facts suggest the hypothesis that a condition of acidosis in the tissues is responsible for the appearance of creatine in the urine. To test it the following questions demand an answer.

I. Will creatine appear in the urine, even in the presence of an abundant carbohydrate supply, if acidosis is induced?

2. Will the elimination of creatine disappear if the acidosis is abolished, quite independently of the factor of carbohydrate supply?

Upon a diet of oats and corn, containing an adequate supply of carbohydrate, creatine promptly appears in the urine of the rabbit. A marked condition of acidosis, as measured by the hydrogen ion concentration of the urine, is always associated with this phenomenon. Oats and corn are pronounced acid-producing foods.