Liver disease and ammonia intoxication

EDITORIAL SYNOPSIS The relation between ammonia intoxication and liver disease is not clear. Ammonia appears to be relatively non-toxic to normal individuals, whereas some patients with liver disease appear to be exquisitely sensitive to dietary protein, ammonia-releasing substances, and ammonium salts. In an attempt to elucidate this relationship the intravenous LD50 ofammonium chloride was determined in both normal mice and in those with liver disease produced by a variety of means. Parenchymal damage was created by acute and chronic carbon tetrachloride intoxication, a low-protein, lipotrope-deficient diet, and mouse hepatitis virus. Mice in which the portal vein had been partially ligated and those infected with Schistosoma mansoni developed portal-systemic collateral circulation. Groups of these mice were placed on high-protein diets and ammonia drinking water for periods as long as two months. A combination of both parenchymal damage and col-lateral circulation was induced in mice either by bile duct ligation or by a combination of schisto-somiasis and acute carbon tetrachloride intoxication. When the above groups of mice with liver disease were compared with normal control mice in the same weight range, the LD50 of ammonium chloride showed no striking change. The coma-engendering effects of ammonia in dog