Observations on the distribution and movement of cadmium in epithelial cells of rat small intestine by light‐ and electron‐microscope radioautography

The localization of cadmium in the absorptive cells of the small intestine has been studied by light- and electron-microscope radioautography at intervals in the first 27 h after intubation of radiocadmium into the stomach of rats. Light-microscope autoradiographic studies showed that cadmium was taken up very quickly by the absorptive cells, and radioactivity in the absorptive layer was disseminated over the entire area of the absorptive cells. Electron-microscope autoradiography showed that there was no concentration of radioactive cadmium in any particular site in the epithelial cells or in the lamina propria. It suggests that the transport mechanism of cadmium through the intestine may be nonspecific. Radioautographic investigation using radiocadmium may provide useful information for cadmium distribution and movement in rat small intestine.