Effects of substance P and somatostatin on choleresis in anesthetized dogs

Six anesthetized dogs were administered three consecutive 30 min infusions of substance P in increasing doses of 1.0, 2.5 and 20 ng kg(-1) min (-1). Five anesthetized dogs were administered 10 min infusions of somatostatin, 0.2 and 1.0 microgram kg(-1) min(-1). The dogs were provided with a common duct fistula and the cystic duct was ligated. The output of total bile, bile acids, sodium, potassium, chloride and bicarbonate was studied in 10 min fractions. Substance P at a dose of 2.5 ng kg(-1) min(-1) and above, reduced the output of total bile, sodium, potassium and chloride by a maximum of 40%, indicating an inhibition of the bile acid independent fraction. The output of bile acids and bicarbonate was unaffected. Both doses of somatostatin reduced all parameters studied by a maximum of 25-45%, indicating inhibition of the bile acid dependent, the bile acid independent and the ductular bile secretion.