Abstract
Radioactive vitamin B_<12> was infused into the upper jejunum with a jejunal tubing and absorption was estimated by Schilling test. The simultaneous administration of ethylenediamineteraacetate drastically reduced absorption of physiological doses of vitamin B_<12> but it exerted no effect on the absorption of supraphysiological doses. The absorption inhibiting effect of EDTA was counteracted by Ca, Mg and Sr ions, but not by ferrous, ferric and Zn ions. When a time interval was placed between the administion of vitamin B_<12> and EDTA, the effect of the latter was no more demonstrable after 3 hours interval. These data, as a whole, suggest that intrinsic factor descends from the stomach in the gut without totally losing activity, and effects absorption of vitamin B_<12> requiring divalent cations such as Ca and Mg.
