Interaction of sodium alkyl sulfates with everted rat small intestinal membrane.

The effect of sodium alkyl sulfates (C6-C14) on the loss of protein from the everted rat small intestine was measured. At a surfactant concentration of 10 mM, a peak effect on protein release was noted with sodium decyl sulfate (C10). Measurement of proten release as a function of sidium lauryl sulfate (C12) concentration resulted in the observation that the effect appears to be due to the micellar phaseof the surfactant solution. At concentrations of C12 above the CMC, the loss of protein from the intestinal preparation increased as the concentration of surfactant was increased. There may be a maximum amount of protein that can be released from the everted rat small intestinal sacs by surface-active agents. At equivalent micellar concentrations of C8-C14 (12.5 times the CMC), there was no difference in the amount of protein released in the presence of the individual alkyl sulfate solutions. Other studies on salicylate transfer across the everted rat small intestine indicate that permeability changes occur with anionic and cationic surfactants but not with nonionics.