Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1983-2-14
pubmed:abstractText
Over the past decade, the non-steroidal antiestrogen tamoxifen has gained general acceptance for the palliative treatment of breast cancer. Although there has been much interest in the pharmacology of tamoxifen, our knowledge of its metabolism in laboratory animals and patients is incomplete and the precise mechanism of action within target tissue and breast tumor cells is unknown. This review briefly describes the pharmacology of tamoxifen in various laboratory species and patients. Several metabolites of tamoxifen are known and their relative potencies as estrogens and antiestrogens are compared with the parent compound. Apart from monohydroxytamoxifen, none of tamoxifen's metabolites are more potent antiestrogens, but a metabolite in the dog, Metabolite E, is fully estrogenic. Routine assays (tlc, HPLC, glc/ms) are available to detect tamoxifen, N-desmethyltamoxifen, monohydroxytamoxifen, and a newly identified metabolite, designated Metabolite Y, in biological fluids. Continuous therapy with tamoxifen (10 mg bid) produces steady-state levels (100-200 ng/ml serum) within 4 weeks. Levels of N-desmethyltamoxifen are often up to twice the levels achieved with tamoxifen, while levels of monohydroxytamoxifen and Metabolite Y are below 10 ng/ml. Although monohydroxytamoxifen has a high binding affinity for the estrogen receptor, the metabolic activation of tamoxifen is an advantage rather than a requirement for antiestrogenic activity. The action of tamoxifen in vivo is the net result of the individual actions of the parent compound and its metabolites competing for the occupation of receptors within target tissues and tumors.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0167-6806
pubmed:author
pubmed:issnType
Print
pubmed:volume
2
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
123-38
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1982
pubmed:articleTitle
Metabolites of tamoxifen in animals and man: identification, pharmacology, and significance.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Review, Research Support, Non-U.S. Gov't