Metabolic consequences of portacaval shunting in the rat

In order to study systematically the physiologic significance of blood from the gastrointestinal tract reaching most tissuesindirectly, after prior exposure to the liver, end-to-side portacaval shunting was carried out in rats. A technique derived from that described by Lee and Fisher was evaluated in more than 140 animals, first as to general applicability and its effects on overall health, body weight, food intake, intestinal absorption and hepatic morphology. In the hands of the authors, and provided that all animals where any doubt as to the patency of the shunt arises during operation are immediately discarded, the procedure used proved reproducible and satisfactory. Specifically, there was good evidence for continued shunt patency for many months postoperatively, while there was no evidence for portal hypertension, for significant collateral circulatory bypass of the shunt, or for hepatic pathology, although liver weight was diminished by about one third, as expected. After an initial loss of 5 to 10% in body weight during the first 2 weeks postoperatively, weight gain resumed and paralleled that in the sham-operated and control animals. The initial weight loss resulted from decreased food intake, not from decreased absorption of one or several components of the diet. The importance of precisely controlled environmental conditions for achieving such limited initial weight loss with prompt resumption of weight gain and good general health has been stressed. The operative procedure used and the conditions selected for the subsequent maintenance of the portacaval shunted animals would thus appear well-suited to the systematic and more detailed analysis of the metabolic and endocrine consequences of portacaval shunting in the rat.