Effect of metabolic acidosis in intestinal absorption of calcium and phosphorus

Am J Physiol. 1980 Dec;239(6):G480-4. doi: 10.1152/ajpgi.1980.239.6.G480.


To investigate the effect of metabolic acidosis on intestinal calcium (Ca) and phosphorus (P) absorption and vitamin D metabolism, metabolic balance studies and in vitro gut sac uptake of 45Ca and [32P]phosphate were performed in rats maintained on low-Ca and moderately low-P diet and fed NH4Cl for 3 or 9 days and pair-fed controls. Plasma 1,25(OH)2D concentration was measured in the rats fed NH4Cl for 9 days and their controls. Net Ca and P absorption was 87-92% in the acidotic rats and did not differ from control. Moreover, gut sac uptakes of 45Ca and [32P]phosphate were not different from control. Plasma 1,25(OH)2D was higher in the ammonium chloride-fed rats than in controls (213 +/- 44 vs. 110 +/- 12 pg/ml), and serum P was lower in the acidotic animals (4.6 +/- 0.7 vs. 7.6 +/- 0.3 mg/dl). These data indicate that metabolic acidosis does not depress the augmented intestinal absorption of calcium and phosphorus noted during their dietary deprivation nor reduce the plasma level of 1,25(OH)2D.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acid-Base Equilibrium*
  • Animals
  • Calcium / blood*
  • Dihydroxycholecalciferols / blood
  • Intestinal Absorption*
  • Magnesium / blood
  • Male
  • Phosphorus / blood*
  • Rats
  • Vitamin D / physiology


  • Dihydroxycholecalciferols
  • Vitamin D
  • Phosphorus
  • Magnesium
  • Calcium