Aboral changes in D-glucose transport by human intestinal brush-border membrane vesicles

D-Glucose transport was investigated in isolated brush-border membrane vesicles from human small intestine. Characteristics of D-glucose transport from the jejunum were compared with that in the mid and terminal ileum. Jejunal and mid-ileal D-glucose transport was Na⁺-dependent and electrogenic. The transient overshoot of jejunal D-glucose transport was significantly greater than corresponding values in mid-ileum. The terminal ileum did not exhibit Na⁺-dependent D-glucose transport, but did exhibit Na⁺-dependent taurocholate transport. Na⁺-glucose co-transport activity by tracer-exchange experiments was greatest in the jejunum, and diminished aborally. We conclude that D-glucose transport in man is Na⁺-dependent and electrogenic in the proximal intestine and directly related to the activity of D-glucose-Na⁺ transporters present in the brush-border membranes. D-Glucose transport in the terminal ileum resembles colonic transport of D-glucose.