CHOLECYSTOKININ IS A SATIETY HORMONE IN HUMANS AT PHYSIOLOGICAL POSTPRANDIAL PLASMA-CONCENTRATIONS

1. Intravenous infusions of the brain/gut hormone, cholecystokinin, ha ve been shown to reduce food intake in a subsequent test meal. However , in previous studies the doses administered were large and likely to have produced plasma concentrations far in excess of the normal post-p randial range, 2, In this study cholecystokinin-8 was infused intraven ously to six healthy subjects in doses that reproduced physiological p ost-prandial concentrations, Plasma concentrations of cholecystokinin were measured using a novel sensitive and specific radioimmunoassay, T he effect of cholecystokinin-8 infusion on subsequent food intake in a standard test meal was compared with the effect of saline infusion in the same subjects, 3. Food intake (mean+/-SEM) was significantly less during cholecystokinin (5092+/-665kJ) than during saline infusion (64 18+/-723kJ, P=0,03), During cholecystokinin infusion, plasma concentra tions increased from 0.45+/-0.06 pmol/l to 7.28+/-2.43 pmol/l immediat ely before the meal, With saline infusion there was no premeal increas e in plasma cholecystokinin concentration, 4, This paper describes a n ovel radioimmunoassay for measurement of plasma concentrations of chol ecystokinin, Using this assay we have demonstrated that cholecystokini n is important in control of satiety in humans.