Effects of cadmium injections on arterial pressure regulation in the rat.

Chronic systolic blood pressure (SBP) studies were conducted in conscious female rats which received single intraperitoneal injections of 0, 100, 200, 1000, or 2000 micrograms Cd (as acetate). All doses of Cd temporarily increased SBP by 10-15 mm Hg between 3-6 days after treatment. Those rats which had received 100 micrograms Cd were then given four additional doses at 14 day intervals. These injections generally produced similar brief SBP elevation. However, sustained hypertension was not produced in any of the protocols. After Cd exposure, SBP was unaffected by substituting saline as the drinking source, but daily water and saline intake were lower in Cd-treated rats. Cd pretreatment did not affect the incidence of hypertension produced by unilateral renal artery constriction but slightly decreased its severity. Administration of Cd had no effect on rats with chronic two kidney renal hypertension. These results suggest that Cd only transiently increased SBP and did not increase susceptibility for developing experimental hypertension.