Influence of plasma bicarbonate concentration and pH on citrate excretion

¹ Departments of Physiology and Medicine, Columbia University College of Physicians and Surgeons, and Presbyterian Hospital, New York City

Citrate excretion has been studied in dogs under various conditions of acid-base balance in order to determine which factors are responsible for the increased citrate clearance present in metabolic alkalosis. A close relationship, significantly modified by systemic pH, was found between plasma bicarbonate concentration and citrate clearance. In the presence of an alkaline plasma pH, there was a linear relationship between changes in plasma bicarbonate concentration and changes in citrate clearance. Other experiments also demonstrated the influence of plasma bicarbonate concentration on citrate clearance at alkaline pH. Under acidotic conditions citrate clearances were low and changes in plasma bicarbonate concentration had little effect on citrate excretion. A change in plasma pH from an acidotic to an alkalotic state, with a constant plasma bicarbonate concentration, produced an increase in citrate clearance. Thus the coexistence in metabolic alkalosis of high plasma bicarbonate concentration and high plasma pH results in a markedly increased citrate clearance.

Key Words: citric acid excretion in dogs • kidney excretion of citric acid • acid-base balance and citrate excretion • metabolic alkalosis and citrate clearance • organic acid excretion

Submitted on August 1, 1963