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Characterization of the recombinant human prostanoid DP receptor and identification of L‐644,698, a novel selective DP agonist
Author(s) -
Hamish Wright D.,
Metters Kathleen M.,
Abramovitz Mark,
FordHutchinson Anthony W.
Publication year - 1998
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0701708
Subject(s) - chemistry , agonist , receptor , radioligand , ligand (biochemistry) , hek 293 cells , stereochemistry , biochemistry
A human embryonic kidney cell line [HEK 293(EBNA)] stably expressing the human recombinant prostaglandin D 2 (PGD 2 ) receptor (hDP) has been characterized with respect to radioligand binding and signal transduction properties by use of prostanoids and prostanoid analogues. Radioligand binding studies included saturation analyses, the effects of nucleotide analogues, the initial rate of ligand‐receptor association and equilibrium competition assays. In addition, adenosine 3′:5′‐cyclic monophosphate (cyclic AMP) generation in response to ligand challenge was also measured, as this is the predominant hDP signalling pathway. L‐644,698 ((4‐(3‐(3‐(3‐hydroxyoctyl)‐4‐oxo‐2‐thiazolidinyl) propyl) benzoic acid) (racemate)) was identified as a novel ligand having high affinity for hDP with an inhibitor constant ( K i ) of 0.9 n m . This K i value was comparable to the K i values obtained in this study for ligands that have previously shown high affinity for DP: PGD 2 (0.6 n m ), ZK 110841 (0.3 n m ), BW245C (0.4 n m ), and BW A868C (2.3 n m ). L‐644,698 was found to be a full agonist with an EC 50 value of 0.5 n m in generating cyclic AMP following activation of hDP. L‐644,698 is, therefore, comparable to those agonists with known efficacy at the DP receptor (EC 50 ): PGD 2 (0.5 n m ), ZK 110841 (0.2 n m ) and BW245C (0.3 n m ). L‐644,698 displayed a high degree of selectivity for hDP when compared to the family of cloned human prostanoid receptors: EP 1 (>25,400 fold), EP 2 (∼300 fold), EP 3‐III (∼4100 fold), EP 4 (∼10000 fold), FP (>25,400 fold), IP (>25,400 fold) and TP (>25,400 fold). L‐644,698 is, therefore, one of the most selective DP agonists as yet described. PGJ 2 and Δ 12 ‐PGJ 2 , two endogenous metabolites of PGD 2 , were also tested in this system and shown to be effective agonists with K i and EC 50 values in the nanomolar range for both compounds. In particular, PGJ 2 was equipotent to known DP specific agonists with a K i value of 0.9 n m and an EC 50 value of 1.2 n m .British Journal of Pharmacology (1998) 123 , 1317–1324; doi: 10.1038/sj.bjp.0701708