Blood pressure and urinary sodium and potassium excretion in cadmium-treated male rats

Subcutaneous injection of cadmium chloride (as CdCl2) in the backs of male Wistar rats at the four doses of 0.01, 0.1, 0.5, and 1.0 mg/kg body wt was performed twice a day for 7 consecutive days and the animals were maintained without any treatment for an additional period up to 60 days. Treatment with 0.1, 0.5, and 1.0 mg Cd markedly decreased the urinary Na and K excretion from Day 1 to Day 3. The significant increase in blood pressure of rats treated with 0.1 mg Cd was not present from Day 8 to Day 32 during which the water retention significantly increased. The blood pressure of rats treated with 1.0 mg Cd significantly increased although the increase in water and Na retention was not observed on Day 32. These observations suggest that the decrease in the urinary excretion of Na and the increase in water retention may be not associated with the main factor for the elevation of the blood pressure induced by Cd. Cd concentrations in the heart, abdominal aorta, and lung of rats treated with 1.0 mg Cd were markedly lower than those in the liver and kidney. Changes in the level of Ca and Mg were only observed in the lung and not in the heart and aorta.