Effect of selenium on blood pressure, urinary sodium excretion and plasma aldosterone in cadmium-treated male rats.

The present study was carried out to help elucidate the possible mechanisms underlying the effect of Cd and the interaction of Se with Cd on blood pressure. Male Wistar rats were divided into four groups: control, Cd-treated, Se-treated, Se-and Cd-treated. Cd and Se were administered at doses of 1.0 mg/kg body weight by subcutaneous injection of aqueous solutions of CdCl2 X 2 X 1/2 H2O and Na2SeO3, respectively. Injections were made either alone or in the Cd + Se treated group, simultaneously at 12-h intervals for 7 consecutive days. All animals were then maintained without further treatment for an additional period of 18 days. Treatment with Cd and Se separately lowered the blood pressure on days 3 and 8, but these levels increased and were significantly higher than that in control rats by day 26. Plasma aldosterone concentrations increased and urinary Na excretion decreased from day 1 to 3 in rats treated with Cd and Se separately. Thereafter, increased water retention precedes the onset of increased blood pressure. From these findings, we suggest that in rats treated with Cd and Se separately the increase in plasma aldosterone is a main factor for decreased urinary Na excretion and increased retention of water, and these factors may be associated with an increase in blood pressure. The treatment with Cd and Se simultaneously decreased urinary Na excretion and increased the plasma aldosterone concentration and water retention before the onset of increased blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)