title: Cysteine supplementation decreases plasma homocysteine concentration in rats fed on a low-casein diet in rats.
abstract: The effect of dietary supplementation with cysteine on the plasma homocysteine concentration was investigated in rats fed on 10% casein (10C) and 30% casein (30C) diets. The 10C diet significantly increased the plasma homocysteine concentration as compared with the 30C diet. The hyperhomocysteinemia induced by the 10C diet was significantly suppressed by cysteine supplementation even at a 0.3% level, whereas cysteine did not decrease the plasma homocysteine concentration when added to the 30C diet. In contrast, 0.3% methionine supplementation of the 10C diet tended to increase the plasma homocysteine concentration. Cysteine supplementation to rats fed on the 10C diet did not alter the plasma cysteine concentration and the hepatic activities of cystathionine beta-synthase and betaine:homocysteine S-methyltransferase, whereas it significantly decreased the hepatic concentrations of S-adenosylmethionine and betaine. These results suggest that cysteine supplementation might be effective for suppressing the hyperhomocysteinemia induced by a low-protein diet.
authors.affiliation: Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okawa
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Morita
authors.forename: Kimio
authors.initials: K
authors.lastname: Sugiyama
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002364:Caseins / Q000494:pharmacology*; D003545:Cysteine / Q000494:pharmacology*; D019587:Dietary Supplements; D006710:Homocysteine / Q000097:blood*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D012436:S-Adenosylmethionine / Q000378:metabolism
chemical_list: D002364:Caseins; D006710:Homocysteine; D012436:S-Adenosylmethionine; D003545:Cysteine