RGD Reference Report - Glucuronidation of acetaminophen catalyzed by multiple rat phenol UDP-glucuronosyltransferases. - Rat Genome Database

Send us a Message



 Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   
Search RGD Grant Resources Citing RGD About Us Contact Us
Genes Projects (beta) QTLs Strains Markers Genome Information Ontologies Cell Lines References Download Submit Data
OntoMate (Literature Search) JBrowse (Genome Browser) Synteny Browser (VCMap)  (beta) Variant Visualizer Multi-Ontology Enrichment (MOET) Gene-Ortholog Location Finder (GOLF) InterViewer (Protein-Protein Interactions) PhenoMiner (Quatitative Phenotypes) Gene Annotator OLGA (Gene List Generator) AllianceMine GViewer (Genome Viewer) Overgo Probe Designer
Aging & Age-Related Disease Cancer & Neoplastic Disease Cardiovascular Disease COVID-19 Developmental Disease Diabetes Hematologic Disease Immune & Inflammatory Disease Infectious Disease Liver Disease Neurological Disease Obesity & Metabolic Syndrome Renal Disease Respiratory Disease Sensory Organ Disease
Find Models   new Genetic Models Autism Models Rat PhenoMiner (Quantitative Phenotypes) Chinchilla PhenoMiner Expected Ranges (Quantitative Phenotype) PhenoMiner Term Comparison Hybrid Rat Diversity Panel Phenotypes GERRC (Gene Editing Rat Resource Center) Phenotypes in Other Animal Models Animal Husbandry Strain Medical Records Phylogenetics Strain Availability Calendar Rats 101 Submissions Photo Archive
Pathways
Rat Community Forum Directory of Rat Laboratories Video Tutorials News RGD Publications RGD Poster Archive Nomenclature Guidelines Resource Links Laboratory Resources Employment Resources

Glucuronidation of acetaminophen catalyzed by multiple rat phenol UDP-glucuronosyltransferases.

Authors: Kessler, FK  Kessler, MR  Auyeung, DJ  Ritter, JK 
Citation: Kessler FK, etal., Drug Metab Dispos 2002 Mar;30(3):324-30.
RGD ID: 634454
Pubmed: PMID:11854153   (View Abstract at PubMed)

Gunn rats glucuronidate acetaminophen (APAP) at reduced rates and show increased susceptibility to APAP-induced hepatotoxicity. This defect is presumed to involve UDP-glucuronosyltransferase (UGT) 1A6, which is nonfunctional in Gunn rats, but it is currently unclear whether other 1A family members are also involved. In humans, two 1A isoforms are known to be active (1A6 and 1A9) but 1A6 form has a 25-fold lower apparent K(m) (2 mM). Rat liver microsomal APAP UGT activity is induced by in vivo treatment with beta-naphthoflavone or oltipraz, an effect correlating with induction of 1A6 and 1A7. To address a possible role of 1A7 in APAP glucuronidation relative to other 1A forms, cDNAs encoding UGTs 1A1, 1A5, 1A6, 1A7, and 1A8 were expressed in human embryonic kidney cells and the contents of expressed enzyme in prepared membrane fractions determined by quantitative immunoblotting. At 2.5 mM APAP, 1A7 showed the highest specific activity (2.8 nmol/min/nmol 1A7 protein), followed by 1A6 (1.1 nmol/min/nmol), and 1A8 (0.27 nmol/min/nmol). 1A1 and 1A5 were essentially inactive. Kinetic comparisons indicated 1A7 had a similar apparent K(m) as 1A6 (4.7 versus 3.9 mM, respectively) but a 2.4-fold higher catalytic activity. These data suggest that in rats, 1A7 plays a major role in APAP glucuronidation and contributes to protection against APAP-induced hepatotoxicity. The involvement of other UGTs besides 1A6 is further underscored by the presence of significant residual APAP-glucuronidating activity by Gunn rat hepatocytes, indicating the activity of an unknown UGT2 family member.



Gene Ontology Annotations    

Biological Process

Molecular Function

Objects Annotated

Genes (Rattus norvegicus)
Ugt1a6  (UDP glucuronosyltransferase family 1 member A6)
Ugt1a8  (UDP glucuronosyltransferase family 1 member A8)

Objects referenced in this article
Gene Ugt1a1 UDP glucuronosyltransferase family 1 member A1 Rattus norvegicus
Gene Ugt1a7c UDP glucuronosyltransferase 1 family, polypeptide A7C Rattus norvegicus

Additional Information