Effect of citrate, glutathione and picolinate on zinc transport by brush border membrane vesicles from rat intestine.

Brush border membrane vesicles were used to evaluate the influence of a variety of potential zinc-binding ligands on zinc transport in the rat. Citrate, glutathione (reduced) and picolinate were added to the extravesicular incubation medium at 0.38 mM. Transport was evaluated for up to 60 minutes at an extravesicular zinc concentration of 0.2 mM. Citrate depressed zinc transport at each time point checked. Picolinate depressed transport after 5 minutes of incubation. Glutathione slightly enhanced transport after 60 minutes of incubation. Neither citrate, glutathione nor picolinate had an influence on D-glucose transport. These results suggest that the compounds evaluated do not enhance zinc transport across the brush border surface of the small intestine of the rat.