The effects of dietary Ca and vitamin D_3 on the Cd accumulation in the liver and the the kidney were observed and discussed in relation with the response to the intestinal Ca transport. 1. Effect of dietary factors was reflected on the concentration of rat serum Ca and 1,25-(OH)_2-D after 2 weeks feeding with experimental diets differing in Cd, Ca and vitamin D_3 level. 2. Ca transport in duodenum was significantly increased by vitamin D_3,especially in the rats raised on low Ca diet. However, this effect was reduced in Cd-exposed rats. 3. Renal Cd accumulation was influenced by neither dietary Ca nor vitamin D_3. However, hepatic Cd accumulation was significantly increased in vitamin D deficient rats, although it was not influenced by dietary Ca. These results suggest that dietary Ca modulates the inhibitory effect of Cd on intestinal vitamin D stimulated Ca transport, but intestinal Cd absorption is rather increased in vitamin D deficient animals.
