EFFECT OF MEDIUM-CHAIN AND LONG-CHAIN TRIGLYCERIDES ON LOWER ESOPHAGEAL SPHINCTER PRESSURE - ROLE OF CCK

Fat meals are known to decrease lower esophageal sphincter (LES) press ure, possibly through postprandial CCK release. Dietary fat consists m ainly of long-chain triglycerides (LCT), which potently stimulate CCK secretion. This effect contrasts with that of medium-chain triglycerid es (MCT), which do not induce CCK release. We recorded LES pressure an d gallbladder volume in six healthy subjects on five separate occasion s during intraduodenal administration of 1) saline control, 2) LCT, 3) MCT, 4) LCT during intravenous infusion of the CCK receptor antagonis t loxiglumide, and 5) MCT together with loxiglumide. LES pressure decr eased significantly during administration of both LCT and MCT. Loxiglu mide completely prevented the reduction in LES pressure during intradu odenal LCT, but; not during intraduodenal MCT. Gallbladder volume decr eased during LCT, but not during MCT. It is concluded that intraduoden al administration of equimolar amounts of both LCT and MCT significant ly reduces LES pressure. The effect of LCT on LES pressure is mediated by CCK. The effect of MCT is not dependent on CCK, since MCT does not release CCK and loxiglumide does not prevent the MCT-induced reductio n in LES pressure.