Effects of lead exposure on renal function in young rats

Abstract

Renal function was evaluated in young rats, 35–50 days old, exposed to lead before weaning via mother's milk and after weaning in their solid diet. Lead-exposed rats had blood lead concentrations of 120±21 μg Pb/100 ml, compared to 10±2 μg Pb/100 ml for pair-fed, age-matched controls. There was no significant difference between the control and lead-exposed groups in body weight, kidney weight, glomerular filtration rate, renal plasma flow, extraction of paraaminohippurate, and fractional excretion of amino acids or phosphate. However, significant differences between control and lead-exposed rats were observed in 24-hr urinary volume excretion and in fractional excretion of sodium following extracellular volume expansion. The elevation in 24-hr urine volume was subsequently demonstrated to be associated with increased water intake in the lead-exposed rats. The results of these studies indicate that in young rats with elevated blood lead concentrations, resting renal function is similar to that found in non-lead-exposed animals. Significant differences in water and electrolyte excretion during stress (water deprivation or extracellular volume expansion) were observed between the control and lead-exposed rats. However, the role of the kidney in the mechanisms involved in these altered responses in unknown.