title: gamma-Tocopherol Accelerated Sodium Excretion in a Dose-Dependent Manner in Rats with a High Sodium Intake.
abstract: We have previously reported that gamma-tocopherol (gamma-Toc) displays a natriuretic potency in rats fed a NaCl diet and administered 20 mg gamma-Toc. In this study, we investigated whether gamma-Toc has natriuretic potency at a dose lower or higher than 20 mg in rats given a NaCl diet. Male rats were fed a control diet or a NaCl diet and administered either placebo or 10, 20 or 40 mg of gamma-Toc. The rat urine was collected for 24 hours (divided into 6 hour periods) and the 2,7,8-trimethyl-2-(2'-carboxyethyl)-6-hydroxychroman (gamma-CEHC) level, the sodium excretion content, and the urine volume were determined. The 24-hour gamma-CEHC and sodium levels in the urine of the NaCl groups given 20 mg or 40 mg gamma-Toc were significantly higher than those in the placebo group. The peak levels of urine sodium and gamma-CEHC in the NaCl group given 40 mg gamma-Toc appeared at 0-6 h, which was a more rapid increase than that seen in the group given 20 mg gamma-Toc. The 24-hour urine volumes of the NaCl groups given 10 and 20 mg gamma-Toc were significantly higher than the urine volume of the placebo group. Our findings suggested that gamma-Toc increased sodium excretion in a dose-dependent manner in rats fed a NaCl diet. Moreover, a high dose of gamma-Toc may accelerate its metabolism and cause an increase in the rate of sodium excretion.
authors.affiliation: Institute of Environmental Science for Human Life, Ochanomizu University, Tokyo 112-8610, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Uto-Kondo
authors.forename: Mariko
authors.initials: M
authors.lastname: Tani
authors.forename: Chikako
authors.initials: C
authors.lastname: Kiyose
authors.forename: Mika
authors.initials: M
authors.lastname: Usuda
authors.forename: Chie
authors.initials: C
authors.lastname: Taguchi
authors.forename: Maiko
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Naoko
authors.initials: N
authors.lastname: Machida
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Kishimoto
authors.forename: Hisako
authors.initials: H
authors.lastname: Saito
authors.forename: Tadahiko
authors.initials: T
authors.lastname: Ueda
authors.forename: Osamu
authors.initials: O
authors.lastname: Igarashi
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kondo