Five dogs were anesthetized, their cystic ducts were ligated, and their common bile ducts cannulated. The experiments were divided into four 1-hour periods.
Taurocholic acid (18 mumol/min) and
pipenzolate methylbromide (0.5 mg/kg
body weight initially followed by 0.1 mg/kg
body weight/20 minutes) were infused during all periods.
Somatostatin (800 ng/kg/min) was infused during periods 2, 3, and 4 to suppress the endogenous secretion of
peptide hormones. During periods 3 and 4,
insulin was infused into a mesenteric vein at rates of 0.2 mU/kg/min and 0.8 mU/kg/min, respectively. These rates have been shown to produce fasting and postprandial portal vein
insulin levels. Bile was collected during each period and the volume,
bile acid concentration, and biliary
lipid content were measured. Another five dogs were studied in a similar way, except that
glucagon was infused in place of
insulin at rates of 0.6 and 3.0 ng/kg
body weight/min to produce fasting and postprandial portal vein levels. The results show that 1) the biliary secretion of
cholesterol and
phospholipid is increased by pharmacologic doses of
somatostatin and 2) physiologic doses of
glucagon, but not
insulin , suppress the biliary secretion of
cholesterol and
phospholipid.