caa a22 4500 465766331 CHVBK 20180323111915.0 cr unu---uuuuu 170327e19900401xx s 000 0 eng 10.1007/BF02535748 doi (NATIONALLICENCE)springer-10.1007/BF02535748 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 [Elektronische Daten] [G. Burton, U. Wronska, L. Stone, D. Foster, K. Ingold] The 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 (d 6-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 (d 0)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 mgd 0-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 mgd 6-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 ford 0- andd 6-RRR-α-TOH by gas chromatography-mass spectrometry. The LE group was similarly divided into three equal subgroups with animals receiving diets containing 5 mgd 6-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 totald 0-+d 6-)RRR-α-TOH concentrations in blood and tissues remained essentially constant over the eight week experiment, whereas in the LE group the totalRRR-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”d 0-RRR-α-TOH nor in the concentrations of "new”d 6-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 documentedin vitro, is of negligible importancein 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. American Oil Chemists' Society, 1990 Burton G. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut Wronska U. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut Stone L. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut Foster D. Division of Biological Sciences, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut Ingold K. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut Lipids Springer-Verlag 25/4(1990-04-01), 199-210 0024-4201 25:4<199 1990 25 11745 https://doi.org/10.1007/BF02535748 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02535748 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Burton G. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut NATIONALLICENCE 700 1- Wronska U. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut NATIONALLICENCE 700 1- Stone L. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut NATIONALLICENCE 700 1- Foster D. Division of Biological Sciences, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut NATIONALLICENCE 700 1- Ingold K. Division of Chemistry, National Research Council of Canada, K1A OR6, Ottawa, Ontario, Canada aut NATIONALLICENCE 773 0- Lipids Springer-Verlag 25/4(1990-04-01), 199-210 0024-4201 25:4<199 1990 25 11745 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer