title: Time-dependent effect of p-aminophenol (PAP) toxicity in renal slices and development of oxidative stress.
abstract: p-Aminophenol (PAP), a metabolite of acetaminophen, is nephrotoxic. This study investigated PAP-mediated changes as a function of time that occur prior to loss of membrane integrity. Experiments further evaluated the development of oxidative stress by PAP. Renal slices from male Fischer 344 (F344) rats (N = 4-6) were exposed to 0.1, 0.25, and 0.5 mM PAP for 15-120 min under oxygen and constant shaking at 37 degrees C. Pyruvate-stimulated gluconeogenesis, adenine nucleotide levels, and total glutathione (GSH) levels were diminished in a concentration- and time-dependent manner prior to detection of a rise in lactate dehydrogenase (LDH) leakage. Glutathione disulfide (GSSG) levels were increased by PAP suggesting the induction of oxidative stress. Western blot analysis confirmed a rise in 4-hydroxynonenal (4-HNE)-adducted proteins in tissues exposed to 0.1 and 0.25 mM PAP for 90 min. The appearance of 4-HNE-adducted proteins at the 0.1 mM concentration of PAP occurred prior to development of increased LDH leakage. Pretreatment with 1 mM glutathione (GSH) for 30 min only partially reduced PAP toxicity as LDH values were less severely depleted relative to tissues not pretreated with GSH. In contrast, pretreatment for 15 min with 2 mM ascorbic acid completely protected against PAP toxicity. Further studies showed that ascorbic acid pretreatment prevented PAP-mediated depletion of GSH. In summary, PAP rapidly depletes GSH and adenine nucleotides and inhibits gluconeogenesis prior to a rise in LDH leakage. PAP induces oxidative stress as indicated by an increase in GSSG and 4-HNE-adducted proteins. Ascorbic acid pretreatment prevents PAP toxicity by maintaining GSH status.
authors.affiliation: Department of Pharmacology, Marshall University, Joan C. Edwards School of Medicine, 1542 Spring Valley Drive Huntington, WV 25704-9388, USA.
authors.forename: R Christopher
authors.initials: RC
authors.lastname: Harmon
authors.forename: Marcus V
authors.initials: MV
authors.lastname: Terneus
authors.forename: Kinsley K
authors.initials: KK
authors.lastname: Kiningham
authors.forename: Monica
authors.initials: M
authors.lastname: Valentovic
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism; D000447:Aldehydes / Q000494:pharmacology; D000627:Aminophenols / Q000633:toxicity*; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D005943:Gluconeogenesis / Q000187:drug effects; D005947:Glucose / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D018384:Oxidative Stress / Q000187:drug effects*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D000227:Adenine Nucleotides; D000447:Aldehydes; D000627:Aminophenols; D000975:Antioxidants; D007770:L-Lactate Dehydrogenase; D005978:Glutathione; D005947:Glucose; C027576:4-hydroxy-2-nonenal; D001205:Ascorbic Acid; C026729:4-aminophenol; D019803:Glutathione Disulfide