The effects of somatostatin and octreotide on the human sphincter of Oddi.

OBJECTIVE: Somatostatin acts at different sites in the human gastrointestinal tract and generally inhibits the release and effects of many gastrointestinal hormones and neuropeptides. Together with its long-acting analogue octreotide, somatostatin is widely used in the treatment of hormone-producing tumours, variceal bleeding, etc., but multi-centre trials have failed to prove a beneficial effect in the treatment of acute pancreatitis or in the prevention of post-ERCP pancreatitis (pancreatitis following endoscopic retrograde cholangiopancreatography). The aim of the present work was to study the effects of somatostatin and octreotide on the human sphincter of Oddi by means of quantitative hepatobiliary scintigraphy (QHBS). METHOD: Fifteen cholecystectomized patients were enrolled in the study, six in the somatostatin group and nine in the octreotide group. QHBS was performed initially with a standard protocol (baseline data), then repeated after 0.1 mg octreotide or a 250 microg bolus + 250 microg/h somatostatin administration. In the 60th min of QHBS, 0.5 mg glyceryl trinitrate (GTN) was administered sublingually. RESULTS: QHBS demonstrated that both somatostatin and octreotide caused a marked impairment in the bile flow: the half-time of excretion (T1/2) over the common bile duct was significantly prolonged compared with baseline data (somatostatin group: common bile duct T1/2 180 min versus 59.7+/-31 min; octreotide group: common bile duct T1/2 140.9+/-60.5 min versus 30.7+/-11.7 min). Glyceryl trinitrate administration accelerated the transpapillary bile flow, with significant decreases in the elevated T1/2 in both groups. CONCLUSION: Increased transpapillary flow induced by glyceryl trinitrate may be beneficial in the treatment of acute or post-ERCP pancreatitis.