Alcohol causes both tolerance and sensitization of rat Kupffer cells via mechanisms dependent on endotoxin.
OBJECTIVE
Ethanol causes both tolerance and sensitization of Kupffer cells. This study was designed to evaluate temporal effects of ethanol in an attempt to understand this paradox.


METHODS
Rats were given ethanol (4 g/kg body wt) intragastrically, and Kupffer cells were isolated 0-48 hours later. After addition of lipopolysaccharide (LPS), intracellular calcium concentration ([Ca2+]i) was measured using a microspectrofluorometer with the fluorescent indicator fura-2, and tumor necrosis factor alpha (TNF-alpha) was measured by enzyme-linked immunosorbent assay. CD14 was evaluated by Western and Northern analysis.


RESULTS
Two hours after ethanol administration, the LPS-induced increase in [Ca2+]i and TNF-alpha release by Kupffer cells was diminished by 50%, and these parameters were reciprocally enhanced twofold at 24 hours. Sterilization of the gut with antibiotics blocked all effects of ethanol on [Ca2+]i and TNF-alpha release completely. Twenty-four hours after ethanol, CD14 in Kupffer cells was elevated about fivefold.


CONCLUSIONS
Kupffer cells isolated from rats early after ethanol exhibited tolerance to LPS, whereas sensitization was observed later. It is likely that both of these phenomena are caused by gut-derived endotoxin and that sensitization in Kupffer cells is caused by increases in CD14.
Laboratory of Hepatobiology and Toxicology, Department of Pharmacology,University of North Carolina at Chapel Hill, North Carolina, USA.
N
N
Enomoto
K
K
Ikejima
B
B
Bradford
C
C
Rivera
H
H
Kono
D A
DA
Brenner
R G
RG
Thurman
D000209:Acute-Phase Proteins; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002469:Cell Separation; D004361:Drug Tolerance / Q000502:physiology; D004731:Endotoxins / Q000097:blood / Q000494:pharmacology*; D000431:Ethanol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D007425:Intracellular Membranes / Q000378:metabolism; D007728:Kupffer Cells / Q000187:drug effects*; D018950:Lipopolysaccharide Receptors / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008562:Membrane Glycoproteins; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D000637:Transaminases / Q000097:blood; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis; D000099231:Lipopolysaccharide-Binding Protein
D000209:Acute-Phase Proteins; D000900:Anti-Bacterial Agents; D002118:Calcium; D002352:Carrier Proteins; D004731:Endotoxins; D000431:Ethanol; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D000637:Transaminases; D014409:Tumor Necrosis Factor-alpha; D000099231:Lipopolysaccharide-Binding Protein