S-adenosyl-L-methionine a counter to lead intoxication?

The effect of S-adenosyl-L-methionine (SAM) administration to both acute and chronic lead exposed mice was investigated. SAM was given s.c. at different doses and for different time intervals. The best results were obtained using 20 mg SAM/kg applied daily over a period of 20-22 days. Results obtained in both acute and chronic lead poisoning were quite similar. GSH concentration in blood and liver, reduced in intoxicated animals was increased after SAM administration reaching normal values. Blood, liver and kidney lead content notably increased at the beginning of SAM treatment and decreased rapidly in the group receiving SAM, attaining values near control levels in 2 weeks. A significant recovery of blood, liver, kidney, spleen and brain delta-aminolevulic acid dehydratase (ALA-D) initially reduced in poisoned animals, was clearly produced after SAM administration. A clear and direct correlation between the recovery of both ALA-D activity and GSH levels and the decreased concentration of lead in tissues was observed, reinforcing our proposal that enhancement of thiol content as a result of SAM administration would facilitate the detoxification process and lead removal, consequently reversing the inactivation of the enzyme. We conclude that SAM therapy is beneficial in the treatment of lead intoxication.