Uptake of water and substances of high molecular weight by the isolated perfused liver during phalloidin poisoning and during increased posthepatic pressure

Abstract

1. Livers of rats were perfused with solutions containing dextran or albumin. 2. Changes in the concentration of dextran or albumin in the perfusion medium due to shifts of water between the intra- and extracellular space of the liver were measured by continous recording the optical rotation of the perfusion medium. 3. The volume of the perfusion medium (i.e. the dextran space of the perfusion apparatus and of the liver) was estimated by measuring the changes in optical rotation of the perfusion medium due to a known dilution. 4. The intracellular space of the liver was calculated from measurements of the dextran or albumin space, the wet weight and the dry weight of the liver. 5. The swelling and the potassium release of the liver poisoned by phalloidin depends strongly on the perfusion pressure. 6. At high perfusion pressures, phalloidin poisoning is followed by an increase of the intracellular space of the liver by about 100%. Accordingly the volume of the perfusion medium diminishes during the poisoning, while the change in the concentration of dextran or albumin in the perfusion medium is very small. Thus the poisoned liver takes up water together with colloids. 7. When the posthepatic pressure is increased, potassium is released and water with dextran (or albumin) is accumulated. The potassium release and the water uptake are reversible. The potassium release is inhibited by 4,7-phenanthroline. 8. The histological changes, due to increased posthepatic pressure, are similar to those in livers poisoned with phalloidin. 9. The results are discussed in respect to the similarity between the effects observed in the phalloidin poisoned livers as well as in the livers perfused with high posthepatic pressure.