Combined effect of tin and lead on heme biosynthesis in rats.

The aim of the present study was to investigate the combined effect of tin (SnCl2) and lead Pb(CH3COO)2 on activity of heme biosynthesis enzymes [delta-aminolevulinic acid synthetase (ALA-S) and heme oxygenase] in liver and kidneys, as well as iron (Fe) and copper (Cu) concentration in serum of rats. The experiment was performed on female rats which received 2 mg Sn/kg and 3.5 mg Pb/kg separately and jointly intraperitoneally (ip) for 5 days and per os (po) at single dose (100 mg Sn/kg and 17.5 mg Pb/kg). Lead induced ALA-S in liver and kidney both after ip and po administration; tin, however, induced ALA-S only after ip administration in liver of rats. The activity of heme oxygenase was induced after Sn po and ip administration in liver and kidneys and Pb administration (ip) in kidneys. Sn and Pb administered jointly caused a significant increase of Cu (ip), whereas Sn (po) decreased this metal level in serum of rats. Kidneys proved to be the organ in which the highest degree of examined enzyme induction took place. Pb is responsible for ALA-S, whereas Sn is responsible for induction of heme oxygenase activity in this organ, especially after per os administration. No additive effect on ALA-S and heme oxygenase activities of Pb and Sn combined was noticed.