Failure of L-arginine to protect in ammonia intoxication: its role in urea source

¹ National Institute of Cardiology of Mexico, Mexico, D. F.

The protective effect of l-arginine against ammonia intoxication produced by ammonium chloride was investigated in dogs. When l-arginine was administered together with NH₄Cl, the increase in blood ammonia was approximately 25% less than when NH₄Cl alone was given. Similar results with these substances were observed in dogs with hyperammoniemia. This protection, however, was only apparent since the variation was not statistically significant. Blood urea rose when NH₄Cl was infused. When l-arginine was added, this increase was even greater and the difference was statistically significant. l-Arginine alone produced a definite rise in blood urea without blood ammonia concentration being affected. The conclusions are drawn that l-arginine does not protect against ammonia intoxication by NH₄Cl and that increase in blood urea is due mainly to the metabolism of exogenous arginine rather than to the transformation of ammonia into urea.