The autoradiographic localisation of retained orally administered cadmium tracer within Paneth cells of rat duodenum

Rats not previously exposed to cadmium and rats whose sole source of drinking water for the previous 9 months contained 0.2 g/litre (200 ppm) cadmium were given 100 microCi Cd109 Cl2 by oral intubation. After 96 h more isotope was retained in the duodenums of rats not previously exposed to cadmium than in the duodenums of cadmium-exposed rats. Autoradiographic studies showed that in the rats not previously exposed to cadmium, radioactivity was concentrated in the Paneth cells at the base of the crypts of Lieberkuhn. This result did not occur in cadmium-exposed rats. Paneth cells are known to contain zinc and metallothionein but their retention of cadmium has not previously been reported. Since exposure to environmental cadmium is largely via contaminated food and water, the role of Paneth cells may be of significance in cadmium toxicology.