Effect of a second metal on cadmium-induced hypertension.

One percent salt, 1 ppm cadmium, or 1 ppm cadmium plus 1 ppm lead in drinking water caused similar mild hypertension in rats. The hypertensive effect of salt, given for 4 months beginning at weaning, disappeared when the salt was withdrawn but subsequently returned without further exposure. Rats continuously given 1 ppm cadmium during and after salt exposure were continuously hypertensive, but salt did not increase their hypertension. Rats continuously exposed to cadmium or cadmium plus lead without extra salt remained hypertensive for 20 months. Rats exposed to cadmium or cadmium plus lead for months 4 through 8 remained hypertensive after metal exposure was discontinued; addition of 0.35 ppm selenium corrected the hypertension in cadmium-fed rats but had little effect in the cadmium plus lead exposed rats.