The purpose of this study was to explore further the relation between the rates of oxygen consumption and
ammonium (NH4+) production in the kidney during chronic
metabolic acidosis. The experimental model was the dog with chronic
metabolic acidosis because of the extensive background literature in this species. Chronic
metabolic acidosis was produced by the ingestion of 10 mmol NH4Cl/kg
body weight for 5 days. There was a significant increase in the rate of
oxygen extraction when
hypernatremia was present. Despite this rise in the rate of oxygen consumption, there was no increase in the rate of NH4+ production nor in the rate of
glutamine extraction. These data suggest that
hypernatremia might prevent a further augmentation in
glutamine extraction when the rate of oxygen consumption rises. In addition, a larger proportion of the NH4+ produced was excreted in the urine during
hypernatremia. This increase was associated with a rise in the urine flow rate, but not with a fall in urine pH.