ALTERATION OF ATRIAL-NATRIURETIC-PEPTIDE LEVELS BY SHORT-TERM CADMIUM TREATMENT

Cadmium (Cd) exposure is known to alter cardiovascular function and has been implicated in the etiology of hypertension. Atrial natriuretic peptide (ANP), a hormone secreted by the heart, has been established as a diuretic, natriuretic, smooth muscle relaxant and may be a modulator of central cardiovascular regulation. The effects of Cd treatment on ANP levels in select tissues were studied as a possible mechanism underlying Cd-induced cardiovascular toxicity. Male rats were injected with CdCl2 (0.01, 0. 1, 0.5 or 1.0 mg/kg, i.p.), twice a day for 7 days and then maintained for a period of 30 days. On experimental day 38 plasma renin activity and plasma ANP content were not significantly altered. The high dose of Cd significantly decreased plasma aldosterone levels and atrial ANP levels on day 38. Hypothalamic ANP was significantly decreased at the 0.1, 0.5 and 1.0 mg/kg doses. Throughout the 37-day period, water consumption was not altered. Urine output was decreased in all treatment groups on day 37. The results indicate that Cd can alter select tissue content of the ANP and this interaction may play an important role in the cardiovascular effects of Cd.