Identification of the gastrointestinal absorption site for cadmium chloride in vivo.

Most models for the study of the mechanism of intestinal absorption of Cadmium (Cd) have been using intestinal tissue in vitro or in situ. The in vivo experiments reported in this article were performed in an attempt to localize the site for gastrointestinal absorption of cadmium chloride during natural physiological conditions by oral exposure of mice to 109Cd-labelled CdCl2. Independent of exposure via drinking water or oral administration of a single dose, Cd was primarily deposited in the most proximal duodenum. Thus the present study as well as others indicate that absorption takes place in the proximal part of the intestine. Absorbed Cd is initially transported to the liver and deposited before being redistributed and accumulated in the kidneys. In this experimental model, dietary tetraethylthiuram disulfide exposure was shown to change the intestinal labelling profile and increase the whole-body retention as well as the intestinal deposition of Cd.