Formula omitted] as a competitive inhibitor of Na +-dependent d-glucose cotransporter in the small intestine brush-border membrane

Abstract

1-O-n- Octyl-β- d-glucopyranoside is a competitive inhibitor of the Na +-dependent d-glucose uptake into rabbit, rat and human intestinal brush-border membrane vesicles. The lack of effect on the equilibrium uptake demonstrates that the detergent does not act by rupturing the vesicles; no membrane leakiness was apparent at the concentrations of octylglucopyranoside used, since d-glucose uptake is not inhibited even in the absence of the Na + gradient (in K + solution). There is a competitive interaction between octylglucopyranoside and d-glucose, as shown by Dixon and by Hunter and Down plots. The selectivity of the detergent effect is confirmed by its modest influence on amino acid uptake.