Gastrointestinal hormones and motility of the human sphincter of Oddi.

We investigated the mechanism of humoral control of bile discharge into the duodenum. The actions of the GB, SO and duodenum were monitered by cinecholecystocholangiogrphy combined with manometry of the SO area using a hydraulic-capillary infusion system or MIKRO-TIP, and these were correlated with the plasma concentrations of GI hormones. We concluded that one of the most significant roles of the sphincter of Oddi is to limit bile flow. This postulation was favored by the observation of so-called 'spasm' of the SO where 8 to 10 contractions per min., in contrast to 'normal' contraction of 2 to 4 per min., were seen. On this special occasion, no discharge of the contrast material into the duodenum was noticed. Exogenous or endogenous CCK causes a coordinated action of the GB contraction, the SO relaxation and relaxation of the adjacent segment of the duodenum, resulting in an effective discharge of bile into the duodenum. The effect of Pancreozymin on bile discharge revealed by endoscopic cinematography was that Pancreozymin first made the orifice of the papilla of Vater widely open with a profuse bile flow and following this, caused a repeated shuttering action of the orifice with minimal discharge of bile. This observation opposes the opinion that active SO contractile activity is necessary to bile flow into the duodenum. Caerulein or CCK-33 caused no 'post-inhibition' enhancement of the SO activity that was seen in case of Pancreozymin administration. Motilin, calcium or other substances contained in Pancreozymin (Boots) might be causative for this enhancement.