title: [Homocysteine metabolism].
abstract: Homocysteine, a sulfur amino acid, is an intermediate metabolite of methionine. In 1969, McCully reported autopsy evidence of extensive arterial thrombosis and atherosclerosis in children with elevated plasma homocysteine concentrations and homocystinuria. On the basis of this observation, he proposed that elevated plasma homocysteine (hyperhomocysteinemia) can cause atherosclerotic vascular disease. Hyperhomocysteinemia is now well established as an independent risk factor for atherosclerotic vascular disease. Mild hyperhomocysteinemia is quite prevalent in the general population. It can be caused by genetic defects in the enzymes involved in homocysteine metabolism or nutritional deficiencies in vitamin cofactors, certain medications or renal disease. An increase of 5 micromol per liter in the plasma homocysteine concentration raises the risk of coronary artery disease by as much as an increase of 20 mg per deciliter in the cholesterol concentration. In this article, we review the biochemical, experimental and clinical studies on hyperhomocysteinemia, with emphasis on the metabolism and pharmacokinetics of homocysteine.
authors.affiliation: Department of Pathophsiology, School of Pharmacy, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji City 192-0392, Japan. tak-hasimoto@q06.itscom.net
authors.forename: Takao
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Shinohara
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hasegawa
mesh_terms: D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase / Q000502:physiology; D000818:Animals; D050940:Betaine-Homocysteine S-Methyltransferase / Q000502:physiology; D002318:Cardiovascular Diseases / Q000209:etiology*; D003903:Deuterium; D008401:Gas Chromatography-Mass Spectrometry; D006073:Gout; D006710:Homocysteine / Q000097:blood / Q000378:metabolism*; D006801:Humans; D020138:Hyperhomocysteinemia; D007553:Isotope Labeling; D008715:Methionine / Q000378:metabolism; D010084:Oxidation-Reduction; D012307:Risk Factors; D012709:Serum Albumin; D014805:Vitamin B 12 / Q000502:physiology
chemical_list: D012709:Serum Albumin; D006710:Homocysteine; D008715:Methionine; D003903:Deuterium; D013766:5-Methyltetrahydrofolate-Homocysteine S-Methyltransferase; D050940:Betaine-Homocysteine S-Methyltransferase; D014805:Vitamin B 12