title: On lowering S-adenosylmethionine.
mesh_terms: D000818:Animals; D007980:Levodopa / Q000378:metabolism / Q000494:pharmacology*; D008099:Liver / Q000201:enzymology; D008745:Methylation; D008780:Methyltransferases / Q000378:metabolism; D009536:Niacinamide / Q000378:metabolism / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D012436:S-Adenosylmethionine / Q000378:metabolism*
chemical_list: D009536:Niacinamide; D007980:Levodopa; D012436:S-Adenosylmethionine; D008780:Methyltransferases; D009638:Norepinephrine