Plasma parathyroid hormone and divalent cation response to induction of acute metabolic acidosis

Abstract

Since the effect of acute administration of acid upon blood magnesium and parathyroid hormone (PTH) is unclear we infused anesthetized dogs with saline (controls), HCl, lactic, and methylmalonic acids for 3 h. In all groups but lactic acid, plasma magnesium decreased; ionized calcium levels were increased by all three acids. Nevertheless, PTH increased in each of six dogs following methylmalonic acid and decreased in four of six animals after lactic acid. The decrease in plasma magnesium concentration after methylmalonic acid appeared to be an important factor in explaining the disparate PTH changes in these two groups because concomitant magnesium administration obviated the increases in PTH in four of six additional methylmalonic acid-infused dogs.