Tests for the absorption of 75Se-labelled homocholic acid conjugated with taurine (75Se-HCAT).
The absorption of selenomethionine Se 75-labelled homocholic acid conjugated with taurine (75-SE-HCAT) was tested in 46 patients. Retention measurements using (1) an uncollimated gamma camera and (2) a measuring arrangement similar to a human-body counter were compared in order to obtain a quantitative assessment of the absorption capacity of the terminal ileum for bile acids. The retention curve obtained after the oral administration of the 75Se-labelled bile-acid analogue showed a monoexponential decline; in the case of unimpaired absorption, the half-life was greater than 2.5 days. When more than 30 cm of the ileum had been eliminated by inflammatory infection or resection, the measured half-life was below 0.5 days due to malabsorption. We also performed a quantitative determination of the hepatic secretion of 75-Se-HCAT into the gall bladder. If more than 80% of the activity administered is found in the gall bladder, disturbed absorption of bile acids in the terminal ileum can be excluded. Values smaller than 80%, however, do not provide proof of disturbed absorption.
D003424:Crohn Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005704:Gallbladder / Q000378:metabolism; D006801:Humans; D007082:Ileum / Q000378:metabolism*; D007408:Intestinal Absorption; D008099:Liver / Q000378:metabolism; D011877:Radionuclide Imaging; D012643:Selenium / Q000378:metabolism*; D013656:Taurocholic Acid / Q000031:analogs & derivatives* / Q000378:metabolism
D013656:Taurocholic Acid; C033638:23-seleno-25-homotaurocholic acid; D012643:Selenium