Metabolic Interrelations Between Intrinsic Factor and Vit. B 12 . ∗ III. B 12 Absorption at Varied Intrinsic Factor Doses

Abstract

Conclusions

Increase in oral dose of intrinsic factor preparations from hog stomach or active gastric materials from humans, with a constant oral dose of vit. B₁₂, up to a certain point, increases the intestinal absorption of vit. B₁₂ as measured by the hepatic uptake of Co⁶⁰-B₁₂. However, further increase in the amount of intrinsic factor may be devoid of any enhancing effect or even result in decreased absorption of B₁₂ in the intestine. The latter might be due to an excessive binding of B₁₂ to the non-absorbed fraction of the intrinsic factor preparation, having high binding capacity for vit. B₁₂.