Influence of cadmium on calcium absorption from the rat intestine

Abstract

Influence of Cadmium on Calcium Absorption from the Rat Intestine. Yuhas, E. M., Miya, T. S., and Schnell, R. C. (1978). Toxicol. Appl. Pharmacol. 43 , 23–31. The effect of cadmium on gastrointestinal calcium absorption in male rats was examined using an in situ single-pass intestinal perfusion technique. The addition of cadmium, (10 −5 , 10 −3 , or 10 −2 m ) to the perfusion medium caused a decrease in net calcium absorption. At Cd concentrations greater than 10 −5 m , a net negative calcium balance occurred. The decrease in net calcium absorption resulted from both a decrease in the lumen-to-plasma flux of calcium (10 −5 to 10 −2 m Cd) and an increase in the plasma-to-lumen flux to calcium (10 −4 to 10 −2 m Cd). Intestinal calcium absorption was unaltered 72 hr following a single acute injection of cadmium acetate (2 mg/kg, ip). In another experiment, rats were given cadmium (0, 1, 10 or 100 ppm) in the drinking water for 13, weeks, and then in situ intestinal calcium absorption was determined. At 1 or 10 ppm of Cd, there was no effect on net calcium absorption or lumen-to-plasma or plasmato-lumen fluxes of calcium. At 100 ppm of Cd, there was an increase in the lumen-to-plasma-to-lumen fluxes of calcium. At 100 ppm of Cd, there was an increase in the lumen-to-plasma flux of calcium since there was no effect on the plasma-to-lumen flux of calcium. While cadmium added to the perfusate may exert a direct inhibitory effect on intestinal calcium absorption, the treatment in vivo of rats with cadmium, either acutely or chronically, does not decrease intestinal calcium absorption.