Renal hypertrophy in metabolic acidosis and its relation to ammonia excretion

Abstract

The chronic ingestion of NH 4 Cl causes a true growth of the rat kidney. This involves a symmetrical increase in wet weight, dry weight, and nitrogen of the kidney tissue. Total DNA and RNA are also elevated, indicating that both cell numbers and cell size have increased. The renal hypertrophy in chronic metabolic acidosis is the same order of magnitude as that seen in the remaining kidney after unilateral nephrectomy. The renal growth-stimulating effects of acidosis and unilateral nephrectomy are additive. In the acidotic rat the renal hypertrophy that occurs after unilateral nephrectomy can maintain a high rate of ammonia excretion without any further change in renal glutaminase activity of the remaining kidney. Thus in certain species the stimulation of renal growth may play a part in the increasing capacity to excrete ammonia during sustained metabolic acidosis.