Effect of intravenous glucagon on the biliary secretion of a cholangiographic agent in man

This study was undertaken in an attempt to define the mechanism whereby intravenous glucagon enhanced bile duct and gallbladder opacification at the time of infusion cholangiography. Seven post-operative gallstone patients with indwelling t-tubes were given a 1 h infusion of intravenous iotroxamide at a rate of 4.1 mg/kg body weight/min. Bile samples were collected by gravity drainage and assayed for iotroxamide and hence biliary iodine concentration. At the end of the 1 h infusion the mean biliary excretion rate (+/- s.e.m.) of iotroxamide was 26.1 +/- 3.4 mg/min and the iodine concentration in bile 9.7 +/- 1.2 mg/ml. 1 mg of intravenous glucagon given over 30 s at the end of the iotroxamide infusion produced a significant increase in bile flow (P less than 0.01). The excretion rate of iotroxamide rose rapidly following glucagon to reach a peak value of 43.8 +/- 8.1 mg/min 5 min after the glucagon (P less than 0.05). The enhanced biliary excretion of iotroxamide resulting from the glucagon injection was significant (P less than 0.05) 1, 3 and 5 but not 10 min after the hormone. The intravenous glucagon also caused a small but significant (P less than 0.05) elevation of the biliary iodine concentration to 10.9 +/- 1.2 mg/ml, 3 min after its injection, but by 5 min post-glucagon the iodine concentration in bile had reversed to pre-injection levels. The possible clinical implications of these results are discussed.