Absorption of selenite in the rat small intestine: interactions with glutathione.

Incubation of isolated rat intestinal epithelial cells with selenite resulted in a rapid decrease of intracellular glutathione (GSH) and about 5 nmol of Se (added as 75Se labelled selenite, 50 microM) was accumulated per 10(6) cells during 20 min. Addition of exogenous GSH enhanced cellular accumulation of Se, while the gamma-glutamyl transferase inhibitor, serine-borate, decreased uptake. The added exogenous GSH was rapidly consumed (oxidized) by selenite. Depletion of GSH by diethylmaleate (DEM) inhibited selenite uptake both in in situ isolated intestinal loop, everted gut sacs and in isolated intestinal cells. The findings indicate that both intracellular and extracellular GSH, and gamma-glutamyltransferase, play a role in the absorption of selenite in the intestine.