消化管におけるカドミウムの毒性, 特にカルシウムとリンの吸収障害について

抄録

There are some reports on the effect of cadmium on calcium metabolism, especially in relation to damage of the renal tobules. We hypothesized that the disturbance of calcium in cadmium intoxication is the result of damage not only of the kidney but also of the intestines. To test this speculation, we fed rats with 10ppm (Cd-10ppm group) or 50ppm (Cd-50ppm group) of cadmium for 287 days.
(1) The calcium and phosphorus absorption rate was decreased to some extent in the Cd-10ppm group. In the Cd-50ppm group, it was significantly decreased starting at the beginning of cadmium feeding.
(2) In the Cd-50ppm group, blood in the feces was most prominent at the beginning of cadmium feeding, and by the 12th day, it had disappeared. After prolonged feeding of cadmium, stool blood increased again. In the Cd-10ppm group, there was no significant melena.
(3) Paraffin sections of the duodenum were stained with hematoxyin-eosin. On the 5th day of 50ppm cadmium feeding, eosinophilic cell infiltration of the submcosa layer and erosion were found, but on the 21th day, no significant abnormality was seen. In the Cd-10ppm group, no abnormality was found.
These observations indicate that the intestinal damage caused by cadmium leads to disorders of calcium metabolism. Further investigation is required to clarify the mechanism of cadmium toxicity in relation to calcium absorption.