title: Adaptations in urea ammonium excretion in metabolic acidosis in the rat: a reinterpretation.
abstract: 1. The effects of oral hydrochloric acid, ammonium chloride, sodium bicarbonate and ammonium bicarbonate on urea and ammonium excretion in rats on a constant diet were studied. 2. Hydrochloric acid acidosis significantly reduced urea excretion in the rat, with an equimolar increase in NH+4 excretion and no change in their sum. In ammonium chloride acidosis, most of the additional nitrogen intake is excreted as NH+4 and a small percentage as urea. The converse holds true after administration of ammonium bicarbonate. The physiological significance of this is discussed. 3. The shift in nitrogen excretion from urea to NH+4 in acidosis is interpreted on the basis of bicarbonate production and utilization. Urea formation utilizes HCO-3. For amino acid sources, this utilization is offset by the metabolism of the carbon skeleton, which gives rise to HCO-3. When waste nitrogen is excreted as NH+4, no bicarbonate is utilized and the new HCO-3, generated by the carbon skeleton, hels to maintain hydrogen ion homeostasis.
mesh_terms: D000138:Acidosis / Q000139:chemically induced / Q000652:urine*; D000222:Adaptation, Physiological; D000643:Ammonium Chloride / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D006851:Hydrochloric Acid / Q000494:pharmacology; D008297:Male; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology / Q000652:urine*; D051381:Rats; D012964:Sodium / Q000494:pharmacology; D014508:Urea / Q000652:urine*
chemical_list: D001639:Bicarbonates; D000644:Quaternary Ammonium Compounds; D000643:Ammonium Chloride; D014508:Urea; D012964:Sodium; D006851:Hydrochloric Acid