The systolic and diastolic pressures in anesthetized Sprague-Dawley male rats were greatly decreased after single-dose of Cd treatment without significant changes in heart rate. There was a fluid-shift into the third space and/or -loss through the kidney, since plasma Na⁢ concentration and hematocrit ratio were significantly increased by acute Cd exposure. The present study showed that the sustained hypotensive effect of single-dose Cd on the cardiovascular system might have resulted from the systemic hypovolemia. Furthermore, renal excretion of electrolytes, including Na⁢ and K⁢, and urine flow rate were increased by Cd intoxication. Interestingly, the ratio of Na⁢/K⁢ excretion was increased and reached the maximum level 3 hours after Cd injection and returned to the normal level after 7 hours. Nevertheless, there was no difference in the regression analysis of K⁢ excretion and urine flow rate in both groups. Therefore, the increase in the urine volume seemed to enhance the excretion of K⁢. This study strongly suggest that the hypotensive effect of Cd is mediated by systemic Na⁢ loss through the kidney and/or hypovolemia via fluid-shift.