[Metabolism of lipid-carrying proteins of rat liver in normal rats and after phenobarbital injection].

A protein fraction possessing a 209 times higher lipid-carrying activity in comparison with the original supernatant (X 105 000 g) was isolated from the livers of Wistar rats. The purification procedure included precipitation at pH 5,1, desalting with ammonium sulfate and gel-filtration through Sephadex G-50. Evidence from polyacrylamide gel electrophoresis suggest that the fraction obtained consists of two components with molecular weights of 18 000 and 30 000. The half-life time of the proteins as determined by double radioactive labelling is 3,7 days. The microsomal oxidation inducer phenobarbital increases the half-life time of lipid-carrying proteins by decreasing their degradation rate.