Abstract
Absorption of vitamin B12 from the proximal jejunum was studied and compared with that of albumin in man employing a three 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 unabsorbable reference, was instilled in the upper jejunum and the decrease of B12:BSP or I131:BSP was determined in the fluid withdrawn at intervals. It was found that absorption of B12 was minimal during the test period of three hours, 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 released B12 further and increased the B12:BSP ratio in about one half of the test subjects, and the results of Schilling test carried out then were consistent with the finding.
