Influence of Selective Hepatic Vascular Perfusion on Ammonia Metabolism in Dog

Abstract

In trying to evaluate the influence of vascular pathways in ammonia clearance by the liver, continuous ammonium chloride perfusions were made separately through the hepatic artery and the portal vein in 20 dogs. Continuous ammonium chloride perfusion (45 mg/kg/hr) through the portal vein results in a highly significant increase in peripheral venous and arterial levels of ammonia, in spite of an ammonia concentration remaining normal in the hepatic vein. On the other hand, continuous ammonium chloride perfusion through the hepatic artery does not significantly change the peripheral ammonia concentration nor the hepatic vein ammonia concentration. From these figures, it must be assumed that during portal perfusion. a fraction of ammonium chloride solution is shunted before reaching the sinusoids. During hepatic artery perfusion, the entire amount of the solution is cleared by the liver and no shunts can be detected. The existence and the level of such shunts are discussed.

Key-words:

• Ammonia
• dog
• hepatic artery
• hepatic, portal vein
• liver circulation