Methyl group balance in brain and liver: Role of choline on increased S-adenosyl methionine (SAM) demand by chronic arsenic exposure

► Chronic arsenic exposure in rats decreases myelin basic protein in the brain. ► Demyelination is not associated with brain depletion of SAM or phosphatidylcholine. ► Chronic arsenic exposure decreases SAM and phosphatidylcholine levels in liver. ► Choline levels increase in the liver of arsenic exposed rats. ► Choline plays an important role as methyl donor in the liver of arsenic exposed rats.