Deuterium‐labeled phylloquinone fed to α‐tocopherol‐injected rats demonstrates sensitivity of low phylloquinone‐containing tissues to menaquinone‐4 depletion. Issue 8 (14th July 2014)

• Record Type: Journal Article
• Authors: Farley, Sherry M.; Leonard, Scott W.; Stevens, Jan F.; Traber, Maret G.; Traber, Maret G.
• Is Part Of: Molecular nutrition & food research. Volume 58:Issue 8(2014:Aug.)
• Page Start: 1610
• Page End: 1619
• Publication Date: 2014-07-14
• Subjects: Food -- Biotechnology -- Periodicals; Food -- Microbiology -- Periodicals; Nutrition -- Periodicals; Food -- Toxicology -- Periodicals; Nutrition -- Periodicals; Food Microbiology -- Periodicals; Food Technology -- Periodicals; Molecular Biology -- Periodicals; 664.0705
• DOI: 10.1002/mnfr.201300659
• Languages: English
• ISSNs: 1613-4125

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="mnfr2226-sec-0010" sec-type="section"> <title>Scope</title> <p>The influence of excess α‐tocopherol (α‐T) on tissue depletion of phylloquinone (PK) and menaquinone‐4 (MK‐4) was evaluated.</p> </sec> <sec id="mnfr2226-sec-0020" sec-type="section"> <title>Methods and results</title> <p>Rats (<italic>n</italic> = 5 per group) were fed deuterium‐labeled PK (2 μmol/kg diet) for 17 days, thereby labeling the conversion from deuterium‐labeled PK to d<sub>4</sub>‐MK‐4. Then they were injected subcutaneously daily for the last 7 days with saline, vehicle, or α‐T (100 mg/kg body weight). α‐T injections (i) increased α‐T concentrations by tenfold in liver, doubled them in plasma and most tissues, but they were unchanged in brain; (ii) increased the α‐T metabolite, carboxyethyl hydroxychromanol (α‐CEHC) concentrations: >25‐fold in liver and kidney, tenfold in plasma and lung, and 50‐fold in heart; brain contained detectable α‐CEHC (0.26 ± 0.03 nmol/g) only in α‐T‐injected animals; and (iii) depleted most tissues' vitamin K. Compared with vehicle‐injected rats, brains from α‐T rats contained half the total vitamin K (10.3 ± 0.5 versus 21 ± 2 pmol/g, <italic>p</italic> = 0.0002) and one‐third the d<sub>4</sub>‐MK‐4 (5.8 ± 0.5 versus 14.6 ± 1.7 pmol/g, <italic>p</italic> = 0.0002). Tissues with high PK concentrations (liver, 21–30 pmol/g and heart, 28–50 pmol/g) were resistant to K depletion.</p> </sec> <sec id="mnfr2226-sec-0030" sec-type="section"> <title>Conclusion</title> <p>We propose that α‐T‐dependent vitamin K depletion is likely mediated at an intermediate step in MK‐4 production; thus, tissues with high PK are unaffected.</p> </sec> </abstract>