Lead-induced hypertension: role of oxidative stress.

Chronic, low-level lead exposure causes hypertension in both animals and humans. The pathogenesis of lead-induced hypertension is multifactorial, including such diverse mechanisms as: inactivation of endogenous nitric oxide and downregulation of soluble guanylate cyclase by reactive oxygen species (ROS), leading to a functional deficiency in nitric oxide; heightened sympathetic activity and plasma norepinephrine together with depressed vascular and elevated renal beta-adrenergic receptor density; elevated plasma angiotensin-converting enzyme (ACE) activity, plasma renin activity (PRA), angiotensin II (Ang-II), and aldosterone levels; increased kininase I and kininase II activities; lead-induced inhibition of vascular smooth muscle Na(+)-K+ ATPase, leading to a rise in cellular Na+ and, hence, Ca2+; and a possible rise in endothelin and thromboxane generation. In this article, we present an overview of the epidemiology and proposed underlying mechanisms of lead-induced hypertension.