Increase In Net Acid Excretion Research Articles

The relationship between urine pH and acid excretion--the influence of urine flow rate.

Abstract Investigation was carried out in normal men to determine the manner by which urine flow rate influences the relationship between urine pH and acid excretion. Subjects excreting an acid urine as a result of the ingestion of ammonium chloride were studied on separate occasions under conditions of normal and high rates of urine flow. Caution was taken to control all other variables known to influence urine acidification. An increase in urine flow rate resulted in an increase in urine pH, a slight increase in net acid excretion, and an increase in ammonium and bicarbonate excretion. The increase in pH could not be explained by a change in blood acid-base parameters nor by an increase in fixed buffering capacity of the high flow urines. The apparent explanation for the increase in urine pH and alteration of net acid composition was provided by the relative unresponsiveness of urine free ammonia concentration [NH 3 ] to changes in urine flow rate. In addition, the results of the present investigation serve to emphasize that urine flow rate must be considered in assessing clinical tests of urine acidification.

The Renal Response to Chronic Hypercarbia and Hypoxaemia in Man

The extracellular acid-base state and renal response to chronic hypercarbia and hypoxaemia have been studied in patients with chronic bronchitis. The results demonstrate that deviations in extracellular hydrogen ion concentrations are frequently present when the arterial carbon dioxide tension exceeds 65 mm Hg, and in some patients incomplete correction of the extracellular pH was found at much lower CO2 tensions. The increase in net acid excretion which results from both acute and chronic CO2 retention is almost entirely in the form of NH4+, which appears to be closely related to the PacO2 and/or arterial pH, and was found to be uninfluenced by prolonged relief of hypoxaemia. The possibility that impairment of ammonia production or excretion might occur in patients with chronic bronchitis during acute exacerbations of their illness receives some support from studies carried out during the administration of ammonium chloride.