Biokinetics of dietary RRR-α-tocopherol in the male guinea pig at three dietary levels of vitamin C and two levels of vitamin E. Evidence that vitamin C does not "spare" vitamin E in vivo

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DOIResolve DOI: http://doi.org/10.1007/BF02535748
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TypeArticle
Journal titleLipids
ISSN0024-4201
Volume25
Issue4
Pages199210; # of pages: 12
Subjectalpha tocopherol; ascorbic acid; animal experiment; article; guinea pig; male; nonhuman; priority journal; vitamin intake; vitamin metabolism; Animal; Ascorbic Acid; Biological Transport, Active; Comparative Study; Deuterium; Diet; Guinea Pigs; Kinetics; Male; Rats; Species Specificity; Support, Non-U.S. Gov't; Tissue Distribution; Vitamin E; Animalia; Cavia; Cavia porcellus; Sus scrofa
AbstractThe net rates of uptake of "new" and loss of "old"2R,4′ R,8′ R-α-tocopherol (RRR-α-TOH, which is natural vitamin E) have been measured in the blood and in nine tissues of male guinea pigs over an eight week period by feeding diets containing deuterium-labelled α-tocopheryl acetate (d6-RRR-α-TOAc). There was an initial two week "lead-in" period during which 24 animals [the "high" vitamin E (HE) group] received diets containing 36 mg of unlabelled (d0)RRR-α-TOAc and 250 mg of ascorbic acid per kg diet, while another 24 animals [the "low" vitamin E (LE) group] received diets containing 5 mg d0-RRR-α-TOAc and 250 mg ascorbic acid per kg diet. The HE group was then tivided into three equal subgroups, which were fed diets containing 36 mg d6-RRR-α-TOAc and 5000 mg [the "high" vitamin C (HEHC) subgroup], 250 mg [the "normal" vitamin C (HENC) subgroup] and 50 mg [the "low" vitamin C (HELC) subgroup] ascorbic acid per kg diet. One animal from each group was sacrificed each week and the blood and tissues were analyzed for d0- and d6-RRR-α-TOH by gas chromatography-mass spectrometry. The LE group was similarly divided into three equal subgroups with animals receiving diets containing 5 mg d6-RRR-α-TOAc and 5,000 mg (LEHC), 250 mg (LENC) and 50 mg (LELC) ascorbic acid per kg diet with a similar protocol being followed for sacrifice and analyses. In the HE group the total d0-+d6-)RRR-α-TOH concentrations in blood and tissues remained essentially constant over the eight week experiment, whereas in the LE group the total RRR-α-TOH concentrations declined noticeably (except in the brain, an organ with a particularly slow turnover of vitamin E). There were no significant differences in the concentrations of "old"d0-RRR-α-TOH nor in the concentrations of "new"d6-RRR-α-TOH found in any tissue at a particular time between the HEHC, HENC and HELC subgroups, nor between the LEHC, LENC and LELC subgroups. We conclude that the long-postulated "spring" action of vitamin C on vitamin E, which is well documented in vitro, is of negligible importance in vivo in guinea pigs that are not oxidatively stressed in comparison with the normal metabolic processes which consume vitamin E (e.g., by oxidizing it irreversibly) or elminate it from the body. This is true both for guinea pigs with an adequate, well-maintained vitamin E status and for guinea pigs which are receiving insufficient vitamin E to maintain their body stores. The biokinetics of vitamin E uptake and loss in the HE guinea pigs are compared with analogous data for rats reported previously (Lipids 22, 163-172, 1987). For most guinea pig tissues the uptake of vitamin E under "steadystate" conditions was faster than for the comparable rat tissues. However, the brain was an exception with the turnover of vitamin E occurring at only one-third of the rate for the rat. © 1990 American Oil Chemists' Society.
Publication date
LanguageEnglish
AffiliationNational Research Council Canada (NRC-CNRC)
Peer reviewedYes
NPARC number21276442
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Record identifier2f1b4108-2831-46cb-bf06-279ba4aac435
Record created2015-10-13
Record modified2016-05-09
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