Linked Life Data

8277508

Source:http://linkedlifedata.com/resource/pubmed/id/8277508

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
26
pubmed:dateCreated
1994-2-4
pubmed:abstractText
The effect of 2- and 4-fluoro substitution on the estrogen receptor-mediated tissue localization of radioiodinated 16 alpha-iodoestradiol (16 alpha-IE2) and its 11 beta-methoxy analogue (11 beta-OMe-16 alpha-IE2) was evaluated. Electrophilic substitution of estrone or 11 beta-methoxyestrone with N-fluoropyridinium salt gave the 2- and 4-fluoro derivatives which were subsequently converted to the 3,17 beta-enol diacetate and brominated to yield exclusively the 16 alpha-bromo analogues. Epimerization gave the corresponding 16 beta-bromoestrones which were reduced to the 17 beta-hydroxy derivatives. Halogen exchange with NaI or Na[125I]I provided the A-ring fluorinated 16 alpha-iodoestradiols. The 4-F analogue exhibited higher affinity for estrogen receptors than the corresponding 2-F analogue, and these differences were more pronounced at higher incubation temperatures. Biodistribution studies in immature female rats showed that 4-fluoro substitution had only a moderate effect on receptor-mediated tissue uptake of the parent molecules whereas 2-fluoro substitution resulted in strongly diminished tissue specificity. The lower target selectivity of the 2-F, compared to the 4-F, analogue correlates to some extent with their different receptor binding properties; however, the rate of catabolism may also be involved. Differences in blood clearance further accentuated the localization properties to yield particularly high uterus to blood ratios in the case of the 4-F-11 beta-OMe-16 alpha-IE2, suggesting the potential of the analog labeled with 123I as a radiopharmaceutical for receptor imaging in nuclear medicine. The isopotential maps of the fluorinated steroids, obtained via semiempirical computer modeling on the molecular structures, show striking differences between the 4-F and 2-F derivatives reflecting their varying biological properties.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0022-2623
pubmed:author
pubmed:issnType
Print
pubmed:day
24
pubmed:volume
36
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4255-63
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
2- and 4-fluorinated 16 alpha(-)[125I]iodoestradiol derivatives: synthesis and effect on estrogen receptor binding and receptor-mediated target tissue uptake.
pubmed:affiliation
MRC Group in the Radiation Sciences, Faculty of Medicine, University of Sherbrooke, Québec, Canada.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't