Relative effects of different surfactants on intestinal absorption and the release of proteins and phospholipids from the tissue.

The actions of anionic, cationic and non-ionic surfactants on the absorptive capability of rat jejunal tissue in vivo were compared with their effects on the amounts of protein and phospholipid released from the mucosal surface under the same conditions. Release of a comparatively small amount of protein was accompanied by large increases in the absorption rates of both L-valine and salicylate, whereas much larger quantities of phospholipid were released before any increase in absorption were observed. Much of the released material appeared to be derived from mucus which was partly degraded after exposure to the higher concentrations of surfactants. The liberation of cholesterol by high concentrations of anionic surfactants suggested that some disruption of the mucosal membrane occurred under those conditions. The relative potency of the surfactants in stimulating both absorption of the solutes and the release of polypeptides and lipids followed the order: anionic greater than non-ionic greater than cationic. The possible pharmaceutical relevance of these findings is discussed.