title: Effect of a histidine-excess diet on a tetrahydrofolylpolyglutamate pattern in rat liver.
abstract: The effect of a histidine-excess diet on the hepatic folylpolyglutamate pattern in rat was studied. Rats were fed ad libitum 9.7% casein basal diets with 0.6% methionine (controls) or the basal diets with 3.5% histidine. The average daily weight gain and the food intake in histidine-supplemented rats (His-rats) did not significantly differ from controls. The liver weight in His-rats, however, was 50% higher than controls. Hepatic methyltetrahydropteroylpentaglutamate (CH3-H4PteGlu5), and tetrahydropteroylmonoglutamate concentrations in His-rats was 5.7- and 2-fold higher than controls, respectively. The tetrahydropteroylpentaglutamate (H4PteGlu5) concentration in the His-rats was 74% lower than controls. Considering the homeostasis of folate cofactors in tissues, these results suggest that the hepatic regeneration systems for H4PteGlu5 in His-rats might be repressed and an apparent methylfolate trap might be attained rather on a pteroylpentaglutamate level than a monoglutamate level, and that the activity for catabolizing the excess histidine might exceed the regenerating activity for folate cofactors.
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kohashi
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: K
authors.initials: K
authors.lastname: Iwai
mesh_terms: D000818:Animals; D002364:Caseins / Q000378:metabolism; D004032:Diet; D005492:Folic Acid / Q000031:analogs & derivatives*; D005527:Food, Fortified; D006639:Histidine / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008715:Methionine / Q000378:metabolism; D009929:Organ Size; D011624:Pteroylpolyglutamic Acids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002364:Caseins; D011624:Pteroylpolyglutamic Acids; D006639:Histidine; D005492:Folic Acid; D008715:Methionine