Rat kidney brush border enzyme activity following subchronic oral lead exposure

Rats received 0.1% lead acetate in their drinking water for 3 weeks or for 6 weeks, at which time renal brush border fractions were obtained for measurement of enzyme activity. Renal brush border preparations from Pb2+-exposed rats exhibited statistically significant decreases in the activity of gamma-glutamyl transpeptidase and alanine aminopeptidase after 3 or 6 weeks of treatment. There was an increase in the activity of alkaline phosphatase which was statistically significant after 3 weeks of Pb2+ exposure. The (Na+,K+) adenosine triphosphatase activity and urokinase activity, located in the basolateral membrane fractions, were unchanged by Pb2+ exposure, as were the protein and phospholipid contents of the brush border fractions. The results are compared to those following acute exposure to Pb2+ or Cd2+.