Effect of chronic ethanol feeding on high density lipoprotein subfractions in rats

We have reported previously that chronic alcohol consumption in the rat produced elevated total serum high density lipoprotein (HDL) fraction, but HDL particles of the alcohol-fed rat were deficient in apolipoprotein (apo) E. In that report, serum HDL particles were prepared by successive ultracentrifugation method and there were concerns that the apo E deficiency in HDL particles was artificially produced by centrifugal forces. In the present report, apo Al affinity column chromatography was used instead of successive ultracentrifugation and it likewise yielded HDL particles from alcohol-fed rats that exhibited lower apo E: apo Al ratio than HDL from control rats (0.185 +/- 0.016 vs. 0.303 +/- 0.017, respectively). When the total serum lipoprotein fraction (d less than 1.21) was analyzed by high performance liquid chromatography (HPLC), both HDL and VLDL peaks were higher in alcohol-fed rats than controls. The size of apo E deficient HDL particles from alcohol-fed rats determined by HPLC did not differ from that of normal HDL particles. When HDL (1.063 less than d less than 1.21) was subfractionated into HDL2 (1.063 less than d less than 1.125) and HDL3 (1.125 less than d less than 1.21), only HDL2 of alcohol-fed rats showed lowered apo E: apo Al ratio when compared with same HDL subfraction of control animals. Therefore, the molecular structure of only HDL2 (but not HDL3) was affected by alcohol-feeding. Another HDL subpopulation which is enriched with apo E, i.e. HDL1 (1.054 less than d less than 1.063), was also prepared.(ABSTRACT TRUNCATED AT 250 WORDS)