Abstract
Anemia is a characteristic of chronic lead-poisoning (1). Although lead might cause anemia solely via its known interference with hemoglobin synthesis (1), lead might also affect the kidney's secretion of erythropoietin (ESF) since lead accumulates in the kidney (2) and is known to impair other renal functions (3). Moreover, with regard to the kidney's endocrine function, we have recently demonstrated that small, acute, iv doses of lead (0.1 mg/kg) raise plasma renin activity (PRA); in contrast, chronic lead poisoning in humans on low salt diets is associated with relatively low PRA (4, 5). There have been no studies of ESF in chronic lead poisoning, but in rats, extremely large, acute, iv doses of lead (40 mg/kg) either reduce (6) or have no effect on (7) the plasma ESF response to hypoxia on the subsequent day. We therefore hypothesized that chronic, low-level, lead-poisoning would reduce the ESF response normally seen in hypoxia; we have tested this hypothesis in rats.
Methods. Experimental protocol. Studies were performed on 48 male Sprague-Dawley rats weighing 355-469 g at the start of the study. For a 6-week period, four groups of 12 rats ate regular rat chow (Tecklad) and drank distilled water containing no lead (Group C-control or non-lead), 0.2 mg Pb/ml as lead acetate (group L,-low dose), 0.4 mg Pb/ml (group M-Medium dose), or 0.6 mg Pb/ml (group H-High dose). Rats were housed four to a cage, and daily fluid intake in each group-cage was measured throughout the six weeks. Thereafter, rats were transferred at 1400 hr to one of two pressure chambers, each of which could accommodate eight rats; food and water were available, Two rats from each of the 4 groups were placed in each chamber; for the next 22 hr pressure was left at atmospheric in one
Get full access to this article
View all access options for this article.