Chronic effects of lead on renin and renal sodium excretion

Rats were chronically given 0.5 mg/ml Pb in drinking water. This produced blood and renal lead concentrations of approximately 30 micrograms/dl and 20 micrograms/gm, respectively, significant kidney swelling, but not change in body weight or hematocrit. After 6 weeks of Pb treatment and during ingestion of a sodium-free diet, PRA was elevated (controls: same diet, not lead), but there was no change in PRS. After 5 months the PRA was significantly higher in the lead-treated group even on a 1% NaCl diet, but the difference between groups disappeared on an Na-free diet; that is, the renin response to sodium deprivation was blunted. As early as 6 weeks after beginning lead treatment, the treated group manifested reduced ability to decrease Na excretion following removal of NaCl from the diet; steady-state sodium excretion was normal on either the 1% NaCl or Na-free diet. We conclude that changes in the renin angiotensin system and renal sodium handling the kidneys of rats.