Stimulation of Vit. B12 Uptake in Tissue Slices by Intrinsic Factor Concentrate.

Abstract

It was demonstrated that intrinsic factor concentrate stimulates the uptake of radioactive vitamin B12 in slices of rat liver and kidney, in vitro. Evidence presented indicates the specificity of this stimulatory action. The stimulation is a function of concentration of intrinsic factor concentrate added, and may therefore be the basis of an in vitro assay for intrinsic factor. It was not necessary to use vitamin B12-deficient tissues to show the stimulation effect and it was observed that hyperthyroidism caused increased uptake of vitamin B12 in the absence of added intrinsic factor concentrate. A brief discussion of the possible function of intrinsic factor is presented.