Release of Vitamin B₁₂‐Binding Protein from Isolated Rat Liver Perfused with a Synthetic Medium

Abstract

The unsaturated vitamin B12-binding capacity (UBBC) of the small molecular size vitamin B12-binding protein (SBP) release and albumin release into the medium and the fluid pressure in the portal vein were studied with respect to their ability to reflect the state of isolated perfused rat liver. The liver was perfused in vitro with a synthetic medium either with or without a gas carrier. Liver damage was induced by hypoxia or noradrenalin. Variations in experimental conditions resulted in different patterns of parameters reflecting different aspects of the liver state. The fluid pressure in the portal vein reflected sensitively the circulatory state but is not always a criterion of the general condition of the isolated liver. The albumin release is a criterion of functional state but did not always reflect liver damage. However, the amount of UBBC of SBP released into the medium is a parameter reflecting sensitively the functional capacity of the liver to produce protein and also seems to indicate liver damage. The use of this parameter provides supplementary information that cannot be obtained by either of the two more conventional parameters.