Recent Advances in Understanding Renal Ammonia Metabolism and Transport

I. David Weiner; Jill W. Verlander


Curr Opin Nephrol Hypertens. 2016;25(5):436-443. 

In This Article

Overview of Renal Ammonia Metabolism

Renal ammonia metabolism differs fundamentally from the excretion of most other urinary solutes. Most urinary solutes are delivered to the kidneys via the renal artery and then are excreted in the urine through a combination of glomerular filtration and renal tubular transport. In contrast, less than 5% of urinary ammonia derives from arterial delivery. Instead, kidneys produce ammonia in a metabolic process that results in equimolar bicarbonate generation. Under basal conditions, ~50% of the ammonia that is produced is excreted in urine and 50% is added to the systemic circulation via renal veins. Changes in urinary ammonia excretion can result either from changes in net ammonia generation or from changes in renal epithelial cell ammonia transport that determines the proportion that is excreted in the urine versus that delivered to the systemic circulation.