Linked Life Data

19280518

Source:http://linkedlifedata.com/resource/pubmed/id/19280518

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2009-3-12
pubmed:abstractText
Zileuton, an agent which targets the leukotriene pathway through inhibition of 5-lipoxygenase (5-LO), was approved for the treatment of asthma in 1997. Shortly after its release, its use was restricted due to the observation of hepatotoxicity in patients. Previous research from the authors' laboratory demonstrated the formation of the reactive metabolite, 2-ABT-S-oxide (M1) from zileuton, and has identified a mercapturate of 2-ABT, C1, in the urine of rats dosed with zileuton. The reaction between M1 and glutathione (GSH) has been established in vitro; however, the potential for catalysis by glutathione transferases (GSTs) was not addressed. The work presented here outlines a role for GSTs in the detoxification of M1. Non-enzymatic conjugation studies with M1 and GSH in control experiments led to a t(1/2) of 6.4 +/- 0.4 h at pH 6.5. This rate was accelerated in the presence of GSTA1-1, GSTM1-1 and GSTP1-1 providing t(1/2) values of 2.6 +/- 0.1, 0.53 +/- 0.02, and 0.3 +/- 0.04 h, respectively, at pH 6.5. The inhibition of various GST enzymes was also studied. Results show that M1 inhibits GSTM1-1 and GSTP1-1 to a greater extent as compared with GSTA1-1. In the case of GSTA1-1, the inhibition was observed to be reversible, whereas M1 inhibition of GSTM1-1 and GSTP1-1 was found to be irreversible under identical conditions. GSTM1-1 is present in liver and thus the finding of the alkylation and potential irreversible inactivation of this isoform in vivo could contribute to an understanding of the hepatotoxicity associated with zileuton.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1366-5928
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
39
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
197-204
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
2-ABT-S-oxide detoxification by glutathione S-transferases A1-1, M1-1 and P1-1: implications for toxicity associated with zileuton.
pubmed:affiliation
Department of Chemistry, University of Virginia, VA, USA. joshiem@lilly.com
pubmed:publicationType
Journal Article, Comparative Study