ROLE OF ALBUMIN AND HIGH-DENSITY-LIPOPROTEIN AS ENDOTOXIN-BINDING PROTEINS IN RATS WITH ACUTE AND CHRONIC ALCOHOL LOADING

In the present study, the role of albumin and high-density lipoprotein (HDL) as endotoxin (Et)-binding proteins in chronically alcohol-fed r ats was studied. In acute ethanol-loaded rats, the Et clearance in the blood was slightly prolonged, and the amount of albumin and HDL-bound Et in the blood was markedly increased. In chronic ethanol-loaded rat s, the Et clearance was significantly faster than that in the control, and HDL-bound Et was increased. In the chronic ethanol-fed rats with an additional 5 g/kg body weight of ethanol toad, the Et clearance was much prolonged, and blood tumor necrosis factor and ALI was elevated, when HDL-bound Et was not further increased. Et-binding capacity of t otal proteins, albumin, and HDL in the hepatocyte culture medium were increased when the Kupffer cells were preincubated in the medium conta ining ethanol, and the resultant culture supernatant was added to the hepatocyte culture system. In the culture experiment in the chronic et hanol-loaded rats, such increases were not observed. These results sug gest that the increase in Et-binding capacity of HDL and albumin may s erve as a protective mechanism against Et in chronic ethanol-loaded ra ts. An addition of high-dose ethanol to these rats may lead to impaire d Et binding and inactivation, which may finally result in increased e ndotoxicity.