ABSORPTION OF VITAMIN B12 FROM THE JEJUNUM IN MAN STUDIED WITH A THREE LUMEN TUBE

Abstract

Vitamin B12 absorption from the proximal jejunum was studied and compared with that of albumin in man employing a 3 lumen tube with an inflatable balloon. A test solution containing physiological doses of radioactive cyanocobalamin (Co57, Co60) or I131-human albumin and bromsulfalein (BSP) as an nonabsorbable reference, was instilled in the upper jejunum and the decrease of B12: BSP or F131: BSP was determined in fluid withdrawn at intervals. B12 absorption was minimal during the test period of 3 hr. whereas I131-human albumin was absorbed quickly and to a much greater extent. After drainage and washing of the jejunum at the end of the test, infusion of EDTA (diethyl-aminetetraacetate) released B12 further and increased the B12: BSP ration in about 1/2 of test subjects, and the Schilling test results were consistent with the finding.