SR27897

EC50: 6 nM (cholecystokinin (CCK1) receptor); Ki: 0.2 nM (cholecystokinin (CCK1) receptor)

In vitro, Lintitript (SR 27897) is a competitive antagonist of cholecystokinin (CCK)-stimulated amylase release in isolated rat pancreatic acini (pA ₂ = 7.50) and of CCK-induced guinea pig gall bladder contractions (pA ₂ = 9.57).
Lintitript produces concentration dependent inhibition of [ ¹²⁵ I]CCK binding to CCK1 receptor sites in the rat pancreas (IC ₅₀ value of 0.58 nM) and also to CCK 2 sites in the guinea pig cortex (IC ₂ value of 479 nM). Lintitript inhibits [ ¹²⁵ I]gastrin binding to gastrin receptors. Lintitript (0.5 nM) increases the dissociation constant of CCK for the CCK A receptor (K _d = 1.8 to 7.2 nM) without modifying the maximum number of receptors (B _max = 1800 to 1770 fmol/mg).

Lintitript (SR 27897; 1 mg/kg, i.v.) completely reverses the CCK-induced amylase secretion. Lintitript also inhibits CCK-induced gastric and gallbladder emptying in mice (ED ₅₀ s = 3 and 72 μg/kg, respectively). Lintitript is also very active (ED ₅₀ = 27 μg/kg p.o.) in the gall bladder emptying protocol with egg yolk as an inducer of endogenous CCK release.