Linked Life Data

18650247

Source:http://linkedlifedata.com/resource/pubmed/id/18650247

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2008-9-22
pubmed:abstractText
Vincristine is metabolized to one primary metabolite, M1, by cDNA-expressed CYP3A4 and CYP3A5 and by CYP3A enzymes in human liver microsomes. For both systems, CYP3A5 is predicted to mediate approximately 80% of the CYP3A metabolism for individuals with high CYP3A5 expression (at least one CYP3A5(*)1 allele). In the current study, the role of CYP3A5 was quantified in the metabolism of vincristine with human cryopreserved hepatocytes. The hepatocytes were genotyped for common CYP3A5 allelic variants (CYP3A5(*)3, CYP3A5(*)6, and CYP3A5(*)7) to predict CYP3A5 expression. For each hepatocyte preparation, the rates of vincristine depletion and metabolite formation were quantified. Whereas human hepatocytes with predicted low CYP3A5 expression did not detectably metabolize vincristine, human hepatocytes with predicted high CYP3A5 expression metabolized vincristine to one primary metabolite, M1. In paired experiments using cryopreserved hepatocytes from the same donor, vincristine was incubated with intact cells and cell lysates supplemented with NADPH. The rates of M1 formation were 4 to 69-fold higher for the cell lysates compared with the intact cells. For one representative donor, the intact cells had a 3-fold higher K(m) value and a 3-fold lower V(max) value for M1 formation compared with the cell lysates. Thus, the rate of M1 formation in the hepatocytes may be influenced by the rate of vincristine translocation across the plasma membrane. We conclude that genetically determined CYP3A5 expression in human cryopreserved hepatocytes plays a major role in vincristine metabolism.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1521-0103
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
327
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
248-57
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Apparent high CYP3A5 expression is required for significant metabolism of vincristine by human cryopreserved hepatocytes.
pubmed:affiliation
Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't, Research Support, N.I.H., Extramural