Metal absorption and the intestinal mucus layer.

The luminal mucus layer of the rat's small intestine was separated from the mucosa by filling the lumen with agar jelly. When the rats were fasted overnight and given 59Fe or 65Zn by stomach tube the mucus isolated by this technique contained more isotope and more sialic acid than fed controls, and more of the isotope was absorbed into the tissues. Saturation and time-course studies showed that the mucus layer has metal-binding activity distinct from that of the mucosa and it is postulated that the mucus layer may play a role in the process of metal absorption.