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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1987-5-29
pubmed:abstractText
New proglumide peptides were synthesized and their inhibitory activity against the cholecystokinin (CCK)-induced relaxation was tested in duodenal circular muscles of hogs in order to locate the active moiety. Isotonic tension is reported as a percentage of the relaxation induced by CCK-4 (4.23 microM) or by Ca-free EGTA (2 mM). In R1-CONHCH(CH2CH2CO-R2)CON(CH2CH2CH3)2, P2-II(R1 = PhCH2O, R2 = Phe33-NH2), its D isomer and P3-I (R1 = Ph, R2 = Asp32-Phe33-NH2) had potent antagonistic activity (IC50 = 47.9 (32.4-72.4) microM, 25.1 (10.0-61.7) microM and 186 (141-240) microM, respectively). Benzotript, from another group of CCK antagonists had an IC50 of 52.5 (40.7-67.6) microM. P2-II (49 microM) or its D isomer (19.6 microM) antagonized non-competitively, and P3-I (168 microM) and benzotript (58.4 microM) antagonized competitively the CCK-4-induced relaxation. P3-I (84 or 168 microM) also antagonized competitively the CCK-8-induced relaxation. The amino acids of Tyr27, Trp30 and Phe33, separately, play important roles for agonist activity for relaxation. Tyr27 is the main relaxing group, Trp30 an antagonistic one and Phe33 is another relaxing one. In the proglumide skeleton, N,N-dipropylglutaramic acid acts like Trp30. Agonist, partial agonist and antagonist activities are exerted by these three groups and bulky substituents.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0014-2999
pubmed:author
pubmed:issnType
Print
pubmed:day
10
pubmed:volume
134
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
181-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1987
pubmed:articleTitle
Proglumide peptides and CCK antagonistic action in hog duodenal circular muscle.
pubmed:publicationType
Journal Article, In Vitro