Effects of chronic alcohol consumption on hepatic poly-ADP-ribosylation in the rat.
BACKGROUND
Poly-adenosine diphosphate (ADP)-ribosylation is involved in a variety of biological processes, which include DNA repair, malignant transformation, and apoptosis. It is of interest how this reaction is altered after long-term alcohol intake. Therefore, we determined long-term alcohol effects on hepatic poly-ADP-ribosylation in the rat.


METHODS
Male Sprague Dawley(R) rats (four pairs) were pair-fed a nutritionally adequate liquid diet that contained ethanol as 36% of total energy and an isocaloric control diets for 4 weeks. Liver tissue homogenates and nuclear fractions were subjected to ADP-ribosylation with [32P]nicotinamide adenine dinucleotide. The ADP-ribosylated proteins were separated by SDS-PAGE, followed by autoradiography. Expression of poly-ADP-ribose polymerase (PARP) also was evaluated by Western blotting.


RESULTS
Incubation of rat liver homogenates in ADP-ribosylation reaction mixture resulted in a radiolabeling of a 116 kDa protein, most likely auto-ribosylation of PARP. This poly-ADP-ribosylation was increased significantly (p < 0.025) after long-term alcohol intake. This alcohol effect was reproducible in nuclear fractions as well. Expression levels of PARP, however, were comparable between alcohol-fed rats and their pair-fed controls.


CONCLUSIONS
Poly-ADP-ribosylation, an important posttranslational modification of nuclear proteins, was increased significantly after chronic alcohol consumption in the rat.
Nomura
F
F
Department of Laboratory and Clinical Medicine, Chiba University School of Medicine, Chiba, Japan. fnomura@ho.chiba-u.ac.jp
Yaguchi
M
M
Itoga And
S
S
Noda
M
M
D000437:Alcoholism / Q000378:metabolism*; D000818:Animals; D001345:Autoradiography; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D002149:Energy Intake; D000431:Ethanol / Q000008:administration & dosage; D008099:Liver / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D009243:NAD / Q000378:metabolism; D011064:Poly Adenosine Diphosphate Ribose / Q000378:metabolism*; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis / Q000378:metabolism; D011506:Proteins / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D011506:Proteins; D009243:NAD; D011064:Poly Adenosine Diphosphate Ribose; D000431:Ethanol; D011065:Poly(ADP-ribose) Polymerases