Distribution of tocopherol and apolipoprotein A-I immunoreactivity in rat liver chromatin

[125I]Labelled lipoproteins (HDL, LDL, and VLDL) are actively taken up by the rat liver. The uptake rate in nonparenchymal liver cells was significantly higher than that in hepatocytes. Analysis of the distribution of the labelled lipoproteins in liver subcellular structures showed the presence of these compounds in the nuclei. The presence of apoA-I, apoB and apoE immunoreactivity in liver cell nuclei was demonstrated by immunochemical methods (ELISA and dot immunoassay). The nuclear matrix and transcriptionally active chromatin displayed the highest apoA-I levels, which considerably exceeded those in the total and transcriptionally inactive chromatins. A similar distribution pattern was observed for alpha-tocopherol. It is concluded that blood serum lipoproteins, primarily HDL, may transport tocopherol and other lipids into cell nuclei.