Intestinal flora is not an intermediate - Printable Version
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Intestinal flora is not an intermediate - sm1693 - 03-27-2018
I've been looking into how the actual conversion takes place. Still a mystery though.
Intestinal flora is not an intermediate in the phylloquinone-menaquinone-4 conversion in the rat.
The ability of male rats to accumulate menaquinone-4 (MK-4) in tissues when fed a vitamin K-deficient diet supplemented with intraperitoneal phylloquinone (K) as the sole source of vitamin K for 14 d was assessed. In both conventionally housed controls and gnotobiotic rats, supplementation with the equivalent of 1500 microg vitamin K/kg diet increased (P < 0.001) tissue MK-4 concentrations above those of controls fed a vitamin K-deficient diet. MK-4 concentrations were approximately 5 ng/g (11 pmol/g) in liver, 14 ng/g in heart, 17 ng/g in kidney, 50 ng/g in brain and 250 ng/g in mandibular salivary glands of gnotobiotic rats. MK-4 concentrations in conventionally housed rats were higher than in gnotobiotic rats in heart (P < 0.01), brain (P < 0.01) and kidney (P < 0.05) but lower in salivary gland (P < 0.05). Cultures of a kidney-derived cell line (293) converted K to the expoxide of MK-4 in a manner that was dependent on both time of incubation and concentration of vitamin K in the media. A liver-derived cell line (H-35) was less active in carrying out this conversion. These data offer conclusive proof that the tissue-specific formation of MK-4 from K is a metabolic transformation that does not require bacterial transformation to menadione as an intermediate in the process.
RE: Intestinal flora is not an intermediate - ChasingGoodandEvil - 09-30-2018
(03-27-2018, 02:46 AM)sm1693 Wrote: I've been looking into how the actual conversion takes place. Still a mystery though.Thats interesting, maybe the bacteria just produce catalysts or precursors for an endogenous reaction
RE: Intestinal flora is not an intermediate - sm1693 - 10-16-2018
I doubt it. My personal experiments show excellent functioning taking in only k1 from greens while doing aggressive antibiotic antifungal measures.