Effect of anaesthetic agents on bile flow and biliary excretion of 131I-cholylglycyltyrosine in the rat.

We have compared in the rat the effects of i.v. anaesthetic agents on bile flow rate and on the biliary excretion of a novel bile acid, 131I-cholylglycyltyrosine (131I-cholylgly.tyr.). Etomidate 1-mg bolus and 2-mg h-1 infusion, Althesin 3-mg bolus and 14.5-mg h-1 infusion and propofol 3.3-mg bolus and 3.3-mg h-1 were given via a tail vein cannula and pentobarbitone 50 mg kg-1 was given by the intraperitoneal route, to groups of six rats. Each animal received only one anaesthetic agent. One hour after cannulation of the common bile duct, 131I-cholylgly.tyr. 5 microCi was injected into the jugular vein and bile was collected every 1 min for 10 min. The mean (SD) percentage cumulative biliary excretion of 131I-cholylgly.tyr. at the end of 10 min was: propofol group 74.1 (5.2)%; Althesin group 82.3 (2.2)%; etomidate group 69.4 (17.6)%; pentobarbitone group 76.4 (3.2)%. Propofol and Althesin were relatively more choleretic, causing bile flow rates twice that produced by pentobarbitone. Only Althesin caused a significant increase in biliary excretion of 131I-cholylgly.tyr. relative to that in rats that received pentobarbitone. Bile flow rates for the respective anaesthetic techniques (microliter min-1/100 g body weight) (mean (SD)) were: propofol group 14.1 (1.8); Althesin group 12.5 (1.7); etomidate 8.5 (1.4); pentobarbitone group 7.3 (1.0). There was a marked metabolic acidosis in all rats except in the propofol group, in which normal acid-base status and oxygenation were observed.