A compact perfusion system for studies on the control of metabolic processes in isolated organs from small animals

A compact apparatus for perfusion of isolated organs from small animals is described. The system is based on a module principle making it useable both in low and high pressure perfusions. 40-80 ml of heparinized, diluted rat blood used as liver-perfusion medium, is recirculated in the system, which is temperature controlled by means of a water jacket. A new type of capillary membrane oxygenator is used for oxygenation. The system permits rapid measurements of perfusate flow, vascular resistance, bile production (when the isolated liver is used), urinary production (when the isolated kidney is used), gas tensions, oxygen consumption, pH and perfusion pressure. Descriptions of the techniques used for operation and perfusion of isolated livers and kidneys from rats are given. By the generally accepted criteria of viability the isolated rat liver remains almost normal for the test period of 3 h. Liver functions were normal as judged by formation of glucose, respiratory rate, urea and bile production and gross morphology. There was very little leakage of liver enzymes into the perfusate. The transformation and elimination of labelled corticosterone were studied to test the steroid metabolizing activity of the isolated rat liver preparation.