Somatostatin Suppression of Canine Fasting Bile Secretion

Somatostatin, a peptide present in hypothalamus, gastric mucosa, and pancreas, suppresses several gastrointestinal functions. We evaluated the effect of graded doses of intravenous somatostatin on taurocholate-stimulated bile flow in awake fasting dogs. Somatostatin doses of 1.5–200 ng × kg^-1 × min^-1 significantly suppressed fasting biliary flow. Biliary lipid concentration showed progressive elevations approaching 200% with 200 ng × kg^-1 × min^-1 somatostatin, while lipid outputs were not altered. The data suggest that somatostatin inhibited bile salt-independent canalicular or ductular secretion, because bile flow, chloride, and bicarbonate output, and the biliary clearance of erythritol were significantly reduced, while bile salt output remained unchanged. In addition, suppression of basal insulin concentration occurred at somatostatin infusion of 200 ng × kg^-1 × min^-1. Additional studies in anesthetized dogs demonstrated that somatostatin could suppress bile secretion without altering hepatic blood flow.