Renal acidification in patients with mineralocorticoid deficiency

Renal acidification was studied in eight patients with Addison's disease or bilateral adrenalectomy receiving glucocorticoid replacement only and without renal insufficiency (group I); in five patients with hyporeninemic hypoaldosteronism and moderate chronic renal insufficiency (group II), and in nine control subjects (group III). During acidosis minimal urine pH was 5.4 or less in all subjects, but excretion of ammonium and titratable acid was moderately reduced in group I and markedly reduced in group II. Bicarbonate excretion at normal serum bicarbonate concentration was trivial in group I subjects and inappropriately elevated in two group II patients.