Linked Life Data

17848096

Source:http://linkedlifedata.com/resource/pubmed/id/17848096

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2007-10-12
pubmed:abstractText
Endogenous estrogen plays a key role in the development of human breast cancer, yet the contribution of specific estrogen metabolites and patterns of estrogen metabolism remains unclear. To determine their individual and joint roles in breast carcinogenesis, it is necessary to be able to measure quantitatively each estrogen metabolite in epidemiologic and clinical biospecimens. In this report, we detail a sensitive, specific, accurate, and precise high-performance liquid chromatography-tandem mass spectrometry method utilizing selected reaction monitoring for measuring the absolute quantities of free (unconjugated) and total (conjugated + unconjugated) endogenous estrogens and estrogen metabolites in human serum from premenopausal and postmenopausal women. The method requires a simple sample preparation and only 0.5 mL of serum, yet is capable of quantifying simultaneously 15 estrogens and estrogen metabolites (EM): estrone and its 2-, 4-, and 16alpha-hydroxy and 2- and 4-methoxy derivatives; 2-hydroxyestrone-3-methyl ether; 17beta-estradiol and its 2-hydroxy and 2- and 4-methoxy derivatives; and estriol, 17-epiestriol, 16-ketoestradiol, and 16-epiestriol. The lower limit of quantitation for each EM was 0.4 pg on-column, equivalent to 8 pg/mL (26.5-29.6 fmol/mL) in the original serum sample. Calibration curves were linear over a 10(3)-fold concentration range. For a stripped serum sample containing 8 pg/mL of each EM, accuracy (percent recovery of a known added amount) ranged from 91 to 113%. Intrabatch precision (including hydrolysis, extraction, and derivatization steps) ranged from 7 to 30% relative standard deviation (RSD), and interbatch precision ranged from 8 to 29% RSD. Since distinct roles have been proposed for many of these estrogen metabolites, an accurate, precise, sensitive, and specific method for measuring their levels in circulation should suggest new approaches to breast cancer prevention, screening, and treatment.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0003-2700
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
7813-21
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Quantitative measurement of endogenous estrogens and estrogen metabolites in human serum by liquid chromatography-tandem mass spectrometry.
pubmed:affiliation
Laboratory of Proteomics and Analytical Technologies, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural, Research Support, N.I.H., Intramural