Linked Life Data

18725509

Source:http://linkedlifedata.com/resource/pubmed/id/18725509

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
11
pubmed:dateCreated
2008-10-20
pubmed:abstractText
Medroxyprogesterone acetate (MPA) is one of the most frequently prescribed progestins for conception, hormone replacement therapy, and adjuvant endocrine therapy. MPA has a low oral bioavailability because of extensive metabolism; however, its metabolism was poorly documented. This study was intended to profile the phase I metabolites of MPA and the cytochrome P450 (P450) isoforms involved. After MPA was incubated with human liver microsomes and the NADPH-generating system, five main metabolites (namely M-1, M-2, M-3, M-4, and M-5) were isolated by high-performance liquid chromatography. Three major metabolites (M-2, M-4, and M-3) were tentatively identified to be 6beta-, 2beta-, and 1beta-hydroxy MPA by liquid chromatography/mass spectrometry and (1)H nuclear magnetic resonance. By consecutive metabolism of purified M-2, M-3, and M-4, M-1 and M-5 were proposed to be 2beta-, 6beta-dihydroxy MPA, and 1,2-dehydro MPA, respectively. CYP3A4 was identified to be the isoform primarily involved in the formation of M-2, M-3, and M-4 in studies with specific P450 inhibitors, recombinant P450s, and correlation analysis. Rat and minipig liver microsomes were included evaluating species differences, and the results showed little difference among the species. In human liver microsomes, the K(m) values ranged from 10.0 to 11.2 muM, and the V(m) values ranged from 194 to 437 pmol/min/mg for M-2, M-3, and M-4. In conclusion, CYP3A4 was the major P450 isoform involved in MPA hydroxylation, with 6beta, 2beta, and 1beta being the possible hydroxylation sites. Minipig and rat could be the surrogate models for man in MPA pharmacokinetic studies.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
1521-009X
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2292-8
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2008
pubmed:articleTitle
Metabolic profiling and cytochrome P450 reaction phenotyping of medroxyprogesterone acetate.
pubmed:affiliation
Laboratory of Pharmaceutical Resource Discovery, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't