The relation of acid base equilibrium in the body to excretion of phosphorus and calcium

The relation of the acid base equilibrium in the animal body to calcium and phosphorus metabolism has been studied by a number of workers. 1 The significance of variation in the acid base equilibrium is undoubted, but considerable confusion is encountered, when an attempt is made to correlate the available results. A good many of the experiments have been done on small animals (rabbits), so that very large doses of acid, for instance, had to be given to obtain effects marked enough to study analytically. Repeated doses of 75 c.c., .9 per cent. HCI given to the rabbits of 1.5 kg. is very considerable and in the experiments of Fitz, Alsberg and Henderson usually finally resulted in death of the animal. Under such conditions, secondary results due to the large amount of acid must have complicated the picture.

This paper is an atixmpt to formulate the relation of acid base equilibrium to the urinary and fecal Ca and P excretion in normal adult man on a uniform mixed diet in which the greater portion of P and Ca are given in an easily available form. Three experiments were done on the effect of administration of HCI and NaHC0₃, the one recorded here showing the effect of base and acid successively on the same diet,. Previous to the days recorded in the tables, the subject had been on the diet for four days. The assumption is made that he was in calcium and phosphorus equilibrium, which is verified by the totals shown in the second table. The experiment was divided into three periods: normal, basic and acid. The P_H of the urine in the normal period was 5.7 to 5.9 and the effect of administration of base and acid is seen clearly.