An experimental method for studying in vivo gallbladder absorption.

A perfusion technique has been developed for the study of net absorption in the gallbaldder of the cat. The lumen of the gallbladder in situ with intact blood vessels and nerves is perfused at a constant rate with bile or a solution of known composition. Differences in volume input and output from the gallbladder are measured with a volume transducer, which in the absence of changes in gallbladder volume reflects net water absorption. By adding polyethylene glycol to the perfusate, net water absorption rate can be calculated from the changes in concentration of this test substance regardless of gallbladder motility. A combined use of these two methods makes possible a concomitant estimation of net water absorption and changes in gallbladder volume. The technique was tested and used for the study of net water absorption from bile, saline and isotonic mannitol solution in the gallbladder lumen.