title: Choline deprivation induces hyperhomocysteinemia in rats fed low methionine diets.
abstract: To clarify the relationship between dietary choline level and plasma homocysteine concentration, the effects of choline deprivation on plasma homocysteine concentration and related variables were investigated in rats fed a standard (25%) casein (25C) diet or standard soybean protein (25S) diet. Using the 25S diet, the time-dependent effect of choline deprivation and the comparative effects of three kinds of lipotropes were also investigated. Feeding rats with the choline-deprived 25S diet for 10 d significantly increased plasma total homocysteine concentration to a level 2.68-times higher than that of the control group, whereas choline deprivation had no effect in rats fed the 25C diet. Increases in hepatic S-adenosylhomocysteine and homocysteine concentrations, decreases in hepatic betaine concentration and the activity of cystathionine beta-synthase, but not betaine-homocysteine S-methyltransferase, and fatty liver also occurred in rats fed the choline-deprived 25S diet. Plasma homocysteine concentration increased when rats were fed the choline-deprived 25S diet for only 3 d, and the increase persisted up to 20 d. The hyperhomocysteinemia induced by choline deprivation was effectively suppressed by betaine or methionine supplementation. Choline deprivation caused hyperhomocysteinemia also in rats fed a choline-deprived low (10%) casein diet. The results indicate that choline deprivation can easily induce prominent hyperhomocysteinemia when rats are fed relatively low methionine diets such as a standard soybean protein diet and low casein diet, possibly through the suppression of homocysteine removal by both remethylation and cystathionine formation. This hyperhomocysteinemia might be a useful model for investigating the role of betaine in the regulation of plasma homocysteine concentration.
authors.affiliation: Department of Applied Biological Chemistry, Faculty of Agriculture, Shizuoka University, Shizuoka, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Setoue
authors.forename: Seiya
authors.initials: S
authors.lastname: Ohuchi
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Morita
authors.forename: Kimio
authors.initials: K
authors.lastname: Sugiyama
mesh_terms: D000818:Animals; D001622:Betaine / Q000032:analysis / Q000494:pharmacology; D002794:Choline / Q000008:administration & dosage*; D002796:Choline Deficiency / Q000097:blood / Q000150:complications*; D003545:Cysteine / Q000097:blood*; D019587:Dietary Supplements; D006128:Growth / Q000502:physiology; D006710:Homocysteine / Q000097:blood*; D020138:Hyperhomocysteinemia / Q000209:etiology*; D008082:Lipotropic Agents / Q000494:pharmacology; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D008082:Lipotropic Agents; D006710:Homocysteine; D001622:Betaine; D008715:Methionine; D003545:Cysteine; D002794:Choline