Zinc and lead interactions on alkaline phosphatase activity (E.C. 3.1.3.1.) in rats

The interactions between zinc and lead in their effect on the biochemical and histochemical activity of alkaline phosphatase were investigated in different parts of the small intestine in rats: in the duodenum, jejunum and ileum, as well as in the liver, kidney and serum. The animals were divided into three experimental groups receiving during 120 days 50 micrograms/ml Zn, 100 micrograms/ml Pb and 50 micrograms/ml Zn + 100 micrograms/ml Pb in deionized water. In the duodenal mucosa in all experimental groups the activity of alkaline phosphatase was raised in relation to controls. The administration of both metals separately increased also the activity of the enzyme in the jejunal mucosa but their joint administration decreased this activity by 28% in relation to the control group. The activity of the enzyme in the ileal mucosa was decreased in all experimental animals. In the homogenates of the liver and kidneys of the rats given only zinc a statistically significant rise was found in the activity of the enzyme. In the remaining experimental groups this activity was decreased. Both metals given separately or jointly increased significantly the activity of the enzyme. Moreover, administration of lead caused a change in the location of alkaline phosphatase in the kidney shifting it towards the basement membrane of the epithelial cells in the convoluted tubules.