Evidence suggesting the 58-kDa acetaminophen binding protein is a preferential target for acetaminophen electrophile.
Acetaminophen is an analgesic and antipyretic which causes liver toxicity in humans and experimental animals with overdose. Acetaminophen (APAP) covalent binding to a cytosolic protein of approximately 58 kDa (58-ABP) has been associated with target organ toxicity. Since hepatic content of 58-ABP varies, studies were conducted to determine if this influences APAP binding to other target proteins. In the liver, the amount of 58-ABP varied with individual male CD-1 mice, but in kidneys of the same mice there was no such variability in 58-ABP content. All male A/J mice tested had comparatively little detectable 58-ABP in liver cytosol. Similarly, female CD-1 mice had low 58-ABP content compared to males; however, administration of testosterone propionate to females significantly increased 58-ABP content in liver cytosol. At 4 hr after challenge of mice from the above-described groups with 600 mg APAP/kg, cytosolic covalent binding to proteins was determined by Western blot analysis with anti-APAP antibody. The Western blots were then stripped of antibody and blocking agents and reprobed with antibody prepared against purified 58-ABP (anti-58-ABP). In the liver, the level of APAP bound to the 58-ABP target corresponded with 58-ABP content. In cases where 58-ABP was poorly expressed, APAP adducts to other protein targets were more prominently detected. In the kidneys of the male CD-1 mice 58-ABP arylation by APAP varied little among animals, reflecting the relatively consistent levels of renal 58-ABP. These data suggest that binding to the 58-ABP may spare other potential targets of APAP electrophile attach and support a role of the 58-ABP as a preferred target of APAP electrophile in cytosol.
Hoivik
D J
DJ
Department of Pharmaceutical Sciences, University of Connecticut, Storrs 06269-2092, USA.
Manautou
J E
JE
Tveit
A
A
Mankowski
D C
DC
Khairallah
E A
EA
Cohen
S D
SD
D000082:Acetaminophen / Q000737:chemistry / Q000378:metabolism; D018712:Analgesics, Non-Narcotic / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000378:metabolism*; D005260:Female; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D051137:Selenium-Binding Proteins; D013739:Testosterone / Q000494:pharmacology
D018712:Analgesics, Non-Narcotic; D002352:Carrier Proteins; C495177:Selenbp2 protein, mouse; D051137:Selenium-Binding Proteins; D000082:Acetaminophen; D013739:Testosterone