title: Demonstration of the innate electrophilicity of 4-(3-(benzyloxy)phenyl)-2-(ethylsulfinyl)-6-(trifluoromethyl)pyrimidine (BETP), a small-molecule positive allosteric modulator of the glucagon-like peptide-1 receptor.
abstract: 4-(3-(Benzyloxy)phenyl)-2-(ethylsulfinyl)-6-(trifluoromethyl)pyrimidine (BETP) represents a novel small-molecule activator of the glucagon-like peptide-1 receptor (GLP-1R), and exhibits glucose-dependent insulin secretion in rats following i.v. (but not oral) administration. To explore the quantitative pharmacology associated with GLP-1R agonism in preclinical species, the in vivo pharmacokinetics of BETP were examined in rats after i.v. and oral dosing. Failure to detect BETP in circulation after oral administration of a 10-mg/kg dose in rats was consistent with the lack of an insulinotropic effect of orally administered BETP in this species. Likewise, systemic concentrations of BETP in the rat upon i.v. administration (1 mg/kg) were minimal (and sporadic). In vitro incubations in bovine serum albumin, plasma, and liver microsomes from rodents and humans indicated a facile degradation of BETP. Failure to detect metabolites in plasma and liver microsomal incubations in the absence of NADP was suggestive of a covalent interaction between BETP and a protein amino acid residue(s) in these matrices. Incubations of BETP with glutathione (GSH) in buffer revealed a rapid nucleophilic displacement of the ethylsulfoxide functionality by GSH to yield adduct M1, which indicated that BETP was intrinsically electrophilic. The structure of M1 was unambiguously identified by comparison of its chromatographic and mass spectral properties with an authentic standard. The GSH conjugate of BETP was also characterized in NADPH- and GSH-supplemented liver microsomes and in plasma samples from the pharmacokinetic studies. Unlike BETP, M1 was inactive as an allosteric modulator of the GLP-1R.
authors: Pharmacokinetics, Dynamics, and Metabolism-New Chemical Entities, Pfizer Worldwide Research and Development, Cambridge, MA 02139, USA.
authors: Heather
authors: H
authors: Eng
authors: Raman
authors: R
authors: Sharma
authors: Thomas S
authors: TS
authors: McDonald
authors: David J
authors: DJ
authors: Edmonds
authors: Jean-Philippe
authors: JP
authors: Fortin
authors: Xianping
authors: X
authors: Li
authors: Benjamin D
authors: BD
authors: Stevens
authors: David A
authors: DA
authors: Griffith
authors: Chris
authors: C
authors: Limberakis
authors: Whitney M
authors: WM
authors: Nolte
authors: David A
authors: DA
authors: Price
authors: Margaret
authors: M
authors: Jackson
authors: Amit S
authors: AS
authors: Kalgutkar
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004355:Drug Stability; D000067757:Glucagon-Like Peptide-1 Receptor; D005978:Glutathione / Q000737:chemistry; D006801:Humans; D008297:Male; D051379:Mice; D008862:Microsomes, Liver / Q000378:metabolism; D011743:Pyrimidines / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018027:Receptors, Glucagon / Q000378:metabolism*
chemical_list: C570819:4-(3-(benzyloxy)phenyl)-2-(ethylsulfinyl)-6-(trifluoromethyl)pyrimidine; C000593833:GLP1R protein, human; C000593834:Glp1r protein, mouse; C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D011743:Pyrimidines; D018027:Receptors, Glucagon; D005978:Glutathione