Lead exposure and changes in the renin-angiotensin-aldosterone system in man

We have studied the effects of chronic slight to moderate lead exposure on the renin-angiotensin-aldosterone system in normotensive man. Plasma renin activity (PRA), blood angiotensin I (AI) concentration, angiotensin converting enzyme (ACE) activity and aldosterone concentration were measured in 33 normotensive men, 25 of whom were occupationally exposed to lead. Positive exponential relationships were found between blood lead and PRA, AI, ACE and aldosterone. Linear relationships were observed between PRA and AI, and between AI and ACE. PRA, AI, and ACE did not significantly correlate with aldosterone. Chronic lead exposure enhanced PRA with a resulting increase in AI levels, which in turn may have produced a substrate-induced increase in ACE. The effects of lead on aldosterone may be mediated in part by an independent pathway. These changes may contribute to the development of hypertension in chronically lead-exposed man.