Reduced secretion of H⁺

Deficiencies in the secretion of H⁺ leads to a reduction in the amount of NH₃ reaching the collecting duct lumen.

If the amount of NH₃ in the renal medulla is reduced (see previous discussion) the [H⁺] in the lumen will rise and inhibit H⁺ secretion.  Urine pH will be low.

In addition, there may be a primary abnormality of H⁺ secretion:

• Abnormalities of the H⁺ ATPase
• Back leak of H⁺ from the tubular lumen into the tubular cell
• Failure of voltage augmentation of distal H⁺ secretion

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