[The effect of captopril on the acidification function of the kidney in hypertension]

The effect of the converting enzyme inhibition treatment on the renal acidification function was studied in 5 mild hypertensive subjects. Before and after one week treatment with daily 75 mg of captopril bicarbonate loading was carried out by peroral administration of 68 mmol NaHCO3. The difference between the partial carbon dioxide tension (pCO2) of the urine and blood [(U-B) pCO2], as well as the pH and bicarbonate values were determined at every hour in the course of 3 hours. In the same persons phosphate loadings were also carried out. Although decrease H+ excretion may follow the suppression of aldosterone, which could be expected in response to the short-term captopril treatment, no such change in distal tubular function could be demonstrated by the sensitive methods administered in this study. It seems to be highly probable, that captopril does not limit the urinary acidifying function in patients with healthy kidneys.