THE DIFFERENTIAL TOXICITY OF AMMONIUM SALTS

Abstract

Intravenous LD 50''s of several ammonium salts were obtained in mice. The ammonia toxicity of the chloride, acetate, bicarbonate, carbonate, and hydroxide salts increased in relation to their effect in raising blood pH. This change appeared to be related either to the effect of pH on the NH3/NH4+ ratio and the ability of ammonia gas to cross the blood-brain-barrier, or to a direct effect of pH on the barrier. The toxicity of ammonium citrate, under the above conditions, does not appear to be related to ammonium toxicity, but to hypocalcemic tetany induced by chelation of calcium by the citrate moiety. These results have been obtained in similar experiments with rabbits and dogs. Therapeutic implications are discussed in the light of the recent findings that respiratory alkalosis is a frequent accompaniment of the hepatic coma syndrome.