Effect of cadmium on plasma aldosterone and serum corticosterone concentrations in male rats

Cadmium chloride (CdCl2) at a dose of 1 mg/kg of body weight was injected into male Wistar rats twice a day (12-hr intervals) for 7 consecutive days. A group of treated rats was maintained without any treatment for an additional period of 10 days and killed on the following day (on Day 18). Plasma aldosterone concentrations were markedly increased in Cd-treated rats on Days 2, 3, and 8. The metabolic clearance rate (MCR) of plasma aldosterone on Day 3 was within the same range as the control value, and the production rate (PR) of aldosterone markedly increased on Day 3, suggesting that the increased plasma aldosterone on Day 3 may be associated with the increase of PR of aldosterone. The serum corticosterone concentration was significantly decreased on Day 8 while the MCR of corticosterone markedly increased on Days 3 and 8 and the PR of corticosterone also significantly increased on Days 3 and 8. The increased ratio (the value in treated rats/the value in control rats) in MCR of corticosterone on Day 8 was higher than that in PR of corticosterone on Day 8, suggesting that the increased MCR was a factor for the decreased serum corticosterone on Day 8. Serum potassium and sodium concentrations significantly increased on Days 1 and 3. No significant differences in Cd contents were observed between the zona glomerulosa and zona fasciculata plus zona reticularis in the Cd-treated rats on Days 3, 8, and 18.