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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2001-11-29
pubmed:abstractText
Structurally new analogs of the peptidic GnRH receptor antagonist Cetrorelix as well as conformationally constrained cyclized deca- or pentapeptides were synthesized and selected peptides evaluated comprehensively. To understand how structural variations of the antagonistic peptide effect pharmacodynamic properties, binding affinities and antagonistic potencies toward the human and rat GnRH receptor were determined. Whereas large substituents in position 6 of linear peptides are compatible with high binding affinity (K(D) < 0.5 nM), all cyclized peptides except the cyclo[3-10] analog D-52391 depicted low binding affinity (K(D) > 10 nM). Binding affinity and antagonistic potency in vitro correlated for all peptides and surprisingly no discrimination between human and rat receptor proteins was observed. Since receptor residues W(101) and N(102) are involved in agonist and antagonist binding, equally potent but structurally different antagonists were tested for binding to the respective W(101)A and N(102)A mutants. In contrast to linear decapeptides, residues N(102) and W(101) are not involved in binding of D-23938 and W(101) is the critical residue for D-52391 binding. We conclude that although equally potent, peptidic GnRH receptor antagonists do have distinct interactions within the ligand binding pocket. Finally, selected antagonists were tested for testosterone suppression in male rats. The duration of testosterone suppression below castration levels differed largely from 1 day for Ganirelix to 27 days for D-23487. Systemic availability became evident as the most important parameter for in vivo efficacy.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-291X
pubmed:author
pubmed:copyrightInfo
(c) 2001 Elsevier Science.
pubmed:issnType
Print
pubmed:day
7
pubmed:volume
289
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
653-63
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11726197-Amino Acid Sequence, pubmed-meshheading:11726197-Animals, pubmed-meshheading:11726197-Binding, Competitive, pubmed-meshheading:11726197-Cell Line, pubmed-meshheading:11726197-Dose-Response Relationship, Drug, pubmed-meshheading:11726197-Gonadotropin-Releasing Hormone, pubmed-meshheading:11726197-Hormone Antagonists, pubmed-meshheading:11726197-Humans, pubmed-meshheading:11726197-Kinetics, pubmed-meshheading:11726197-Male, pubmed-meshheading:11726197-Mice, pubmed-meshheading:11726197-Peptides, pubmed-meshheading:11726197-Peptides, Cyclic, pubmed-meshheading:11726197-Rats, pubmed-meshheading:11726197-Rats, Sprague-Dawley, pubmed-meshheading:11726197-Receptors, LHRH, pubmed-meshheading:11726197-Structure-Activity Relationship, pubmed-meshheading:11726197-Testosterone
pubmed:year
2001
pubmed:articleTitle
Structure-function studies of linear and cyclized peptide antagonists of the GnRH receptor.
pubmed:affiliation
Department of Cancer Research, ASTA Medica AG, Weismüllerstrasse 45, 60314 Frankfurt/Main, Germany. T.Beckers@vff.uni-frankfurt.de
pubmed:publicationType
Journal Article