Thromb Haemost 2008; 100(04): 530-547
DOI: 10.1160/TH08-03-0147
Theme Issue Article
Schattauer GmbH

Metabolism and cell biology of vitamin K

Martin J. Shearer
1   Centre for Haemostasis and Thrombosis, Guy’s & St Thomas’ NHS Foundation Tr ust, London, UK
,
Paul Newman
2   Epithelial Cell Biology Laboratory, Cancer Research UK, Cambridge Research Institute, Cambridge
› Author Affiliations
Further Information

Publication History

Received 07 March 2008

Accepted after minor revision 17 July 2008

Publication Date:
22 November 2017 (online)

Summary

Naturally occurring vitamin K compounds comprise a plant form, phylloquinone (vitamin K1) and a series of bacterial menaquinones (MKs) (vitamin K2). Structural differences in the isoprenoid side chain govern many facets of metabolism of K vitamins including the way they are transported, taken up by target tissues, and subsequently excreted. In the post-prandial state, phylloquinone is transported mainly by triglyceride-rich lipoproteins (TRL) and long-chain MKs mainly by low-density lipoproteins (LDL). TRL-borne phylloquinone uptake by osteoblasts is an apoE-mediated process with the LRP1 receptor playing a predominant role. One K2 form, MK-4, has a highly specific tissue distribution suggestive of local synthesis from phylloquinone in which menadione is an intermediate. Both phylloquinone and MKs activate the steroid and xenobiotic receptor (SXR) that initiates their catabolism, but MK-4 specifically upregulates two genes suggesting a novel MK-4 signalling pathway. Many studies have shown specific clinical benefits of MK-4 at pharmacological doses for osteoporosis and cancer although the mechanism(s) are poorly understood. Other putative non-cofactor functions of vitamin K include the suppression of inflammation, prevention of brain oxidative damage and a role in sphingolipid synthesis. Anticoagulant drugs block vitamin K recycling and thereby the availability of reduced vitamin K. Under extreme blockade, vitamin K can bypass the inhibition of Gla synthesis in the liver but not in the bone and the vessel wall. In humans, MK-7 has a greater efficacy than phylloquinone in carboxylating both liver and bone Gla proteins. A daily supplement of phylloquinone has shown potential for improving anticoagulation control.

 
  • References

  • 1 Collins MD, Jones D. Distribution of isoprenoid quinone structural types in bacteria and their taxonomic implications. Microbiol Rev 1981; 45: 316-354.
  • 2 Ramotar K. et al. Production of menaquinones by intestinal anaerobes. J Infect Dis 1984; 150: 213-218.
  • 3 Conly JM, Stein K. Quantitative and qualitative measurements of K vitamins in human intestinal contents. Am J Gastroenterol 1992; 87: 311-316.
  • 4 Suttie JW. The importance of menaquinones in human nutrition. Annu Rev Nutr 1995; 15: 399-417.
  • 5 Schurgers LJ, Vermeer C. Determination of phylloquinone and menaquinonesin food. Haemostasis 2000; 30: 298-307.
  • 6 Booth SL. et al. Phylloquinone (vitamin K1) content of foods in the U. S. Food and Drug Administration’sTotal Diet Study. J Agric Food Chem 1995; 43: 1574-1579.
  • 7 Bolton-Smith C. et al. Compilation of a provisional UK database for the phylloquinone (vitamin K1) content of foods. Br J Nutr 2000; 83: 389-399.
  • 8 Thane CW. et al. Intake and sources of phylloqui-none (vitamin K1): variation with socio-demographic and lifestyle factors in a national sample of British elderly people. Br J Nutr 2002; 87: 605-613.
  • 9 Thane CW. et al. Comparative dietary intake and sources of phylloquinone (vitamin K1) among British adults in 1986-7 and 2000-1. Br J Nutr 2006; 96: 1105-1115.
  • 10 Booth SL, Suttie JW. Dietary intake and adequacy of vitamin K. J Nutr 1998; 128: 785-788.
  • 11 Schurgers LJ. et al. Nutritional intake of vitamins K1 (phylloquinone) and K2 (menaquinone) in the Netherlands. J Nutr Environm Med 1999; 09: 115-122.
  • 12 Hojo K. et al. Quantitative measurement of tetrahy-dromenaquinone-9 in cheese fermented by propionibacteria. J Dairy Sci 2007; 90: 4078-4083.
  • 13 Salminen S. et al. Functional food science and gastrointestinal physiology and function. Br J Nutr 1998; 80: S147-S147.
  • 14 Mathers JC. et al. Dietary modification of potential vitamin K supply from enteric bacterial menaquinones in rats. Br J Nutr 1990; 63: 639-652.
  • 15 Shearer MJ. Vitamin K metabolism and nutriture. Blood Rev 1992; 06: 92-104.
  • 16 Blomstrand R, Forsgren L. Vitamin K1-3H in man. Its intestinal absorption and transport in the thoracic duct in lymph. Int Z Vitaminforsch 1968; 38: 45-64.
  • 17 Kohlmeier M. et al. Transport of vitamin K to bone in humans. J Nutr 1996; 126: 1192S-1196S.
  • 18 Lamon-Fava S. et al. Plasma lipoproteins as carriers of phylloquinone (vitamin K1) in humans. Am J Clin Nutr 1998; 67: 1226-1231.
  • 19 Schurgers LJ, Vermeer C. Differential lipoprotein transport pathways of K-vitamins in healthy subjects. Biochim Biophy Acta 2002; 1570: 27-32.
  • 20 Erkkilä AT. et al. Plasma transport of vitamin K in men using deuterium-labeled collard greens. Metabolism 2004; 53: 215-221.
  • 21 Jones KS. et al. A stable isotope method for the simultaneous measurement of vitamin K1 (phylloquinone) kinetics and absorption. Eur J Clin Nutr. 2007 Epub: In press.
  • 22 Olson RE. et al. To tal body phylloquinone and its turnover in human subjects at two levels of vitamin K intake. Brit J Nutr 2002; 87: 543-553.
  • 23 Shearer MJ. et al. Studies on the absorption and metabolism of phylloquinone (vitamin K1) in man. Vitamins and Hormones 1974; 32: 513-542.
  • 24 Hodges SJ. et al. Detection and measurement of vitamins K1 and K2 in human cortical and trabecular bone. J Bone Miner Res 1993; 08: 1005-1008.
  • 25 Hagstrom JN. et al. The pharmacokinetics and lipoprotein fraction distribution of intramuscular vs. oral vitamin K1 supplementation in women of childbearing age: effects on hemostasis. Thromb Haemost 1995; 74: 1486-1490.
  • 26 Schurgers LJ. et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood 2007; 109: 3279-3283.
  • 27 Cooper AD. Hepatic uptake of chylomicron remnants. J Lipid Res 1997; 38: 2173-2192.
  • 28 Vermeer C. et al. Beyond deficiency: potential benefits of increased intakes of vitamin K for bone and vascular health. Eur J Nutr 2004; 43: 325-335.
  • 29 Sato T. et al. Difference in the metabolism of vitamin K between liver and bone in vitamin K-deficient rats. Br J Nutr 2002; 87: 307-314.
  • 30 Price PA, Kaneda Y. Vitamin K counteracts the effect of warfarin in liver but not in bone. Thromb Res 1987; 46: 121-131.
  • 31 Newman P. et al. The uptake of lipoprotein-borne phylloquinone (vitamin K1) by osteoblasts and osteob-last-like cells: role of heparan sulfate proteoglycans and apolipoprotein E. J Bone Miner Res 2002; 17: 426-433.
  • 32 Weintraub MS. et al. Dietary fat clearance in normal subjects is regulated by genetic variation in apolipoprotein E. J Clin Invest 1987; 80: 1571-1577.
  • 33 Schilling AF. et al. Increased bone formation in mice lacking apolipoprotein E. J Bone Miner Res 2005; 20: 274-282.
  • 34 Niemeier A. et al. Expression of LRP1 by human osteoblasts: a mechanism for the delivery of lipoproteins and vitamin K1 to bone. J Bone Miner Res 2005; 20: 283-293.
  • 35 Niemeier A. et al. Uptake of postprandial lipoproteins into bone in vivo: Impact on osteoblast function. Bone 2008; 43: 230-237.
  • 36 Shearer MJ. et al. The assessment of human vitamin K status from tissue measurements. Current Advances in Vitamin K Research. New York: Elsevier; 1988: 437-452.
  • 37 Thijssen HHW, Drittij-Reijnders MJ. Vitamin K status in human tissues: tissue specific accumulation of phylloquinone and menaquinone-4. BrJ Nutr 1996; 75: 121-127.
  • 38 Usui Y. et al. Vitamin K concentrations in the plasma and liver of surgical patients. Am J Clin Nutr 1990; 51: 846-852.
  • 39 Thijssen HHW, Drittij-Reijnders MJ. Vitamin K distribution in rat tissues: dietary phylloquinone is a source of tissue menaquinone-4. Br J Nutr 1994; 72: 415-425.
  • 40 Slater EC. The possible function of quinols, chromanols and chromenols in intracellular respiration. Am J Clin Nutr 1961; 09: 50-60.
  • 41 Martius C, Esser HO. Über die Konstitution des im Tierkörper aus Methylnaphthochinon gebildeten K-Vitamines. Biochem Z 1958; 331: 1-9.
  • 42 Martius C. The metabolic relationships between the different K vitamins and the synthesis of the ubiquinones. Am J Clin Nutr 1961; 09: 97-103.
  • 43 Billeter M, Martius C. Über die Umwandlung von Phyllochinon (vitamin K1) in Vitamin K2(20) im Tier-körper. Biochem Z 1960; 333: 430-439.
  • 44 Billeter M. et al. Untersuchungen über die Umwandlung von verfütterten K-Vitaminen durch Austauch der Seitenkette und die Rolle der Darmbakterien hierbei. Biochem Z 1964; 340: 290-303.
  • 45 Will BH. et al. Comparative metabolism and requirement of vitamin K in chicks and rats. J Nutr 1992; 122: 2354-2360.
  • 46 Ronden JE. et al. Intestinal flora is not an intermediate in the phylloquinone-menaquinone-4 conversion in the rat. Biochim Biophys Acta 1998; 1379: 69-75.
  • 47 Davidson RT. et al. Conversion of dietary phylloquinone to tissue menaquinone-4 in rats is not dependent on gut bacteria. J Nutr 1998; 128: 220-223.
  • 48 Yamamoto R. et al. Menaquinone-4 accumulation in various tissues after an oral administration of phylloquinone in Wistar rats. J Nutr Sci Vitaminol (Tokyo) 1997; 43: 133-143.
  • 49 IARC nographs on the Evaluation of Carcinogenic Risks to Humans. Some antiviral and antineoplastic drugs, and other pharmaceutical agents. Vitamin K substances. IARC Press 2000; 76: 417-486.
  • 50 Thijssen HHW. et al. Menadione is a metabolite of oral vitamin K. Br J Nutr 2006; 95: 260-266.
  • 51 Okano T. et al. Conversion of phylloquinone (vitamin K1) into menaquinone-4 (vitamin K2) in mice: Tw o possible routes for menaquinone-4 accumulation in cerebra of mice. J Biol Chem 2008; 283: 11270-11279.
  • 52 Dialameh GH. et al. Enzymatic alkylation of menaquinone-0 to menaquinonesby microsomes from chick liver. Biochim Biophys Acta 1970; 223: 332-338.
  • 53 Booth SL. et al. Age and dietary form of vitamin K affect menaquinone-4 concentrations in male Fischer 344 rats. J Nutr 2008; 138: 492-496.
  • 54 Konishi T. et al. Whole-body autoradiographic study of vitamin K distribution in rat. Chem Pharm Bull (To kyo) 1973; 21: 220-224.
  • 55 Groenen-van Dooren MM. et al. Bioavailability of phylloquinone and menaquinones after oral and colorectal administration in vitamin K-deficient rats. Biochem Pharmacol 1995; 50: 797-801.
  • 56 Shearer MJ, Barkhan P. Studies on the metabolites of phylloquinone (vitamin K1) in the urine of man. Biochim Biophys Acta 1973; 297: 300-312.
  • 57 McBurney A. et al. Preparative isolation and characterization of the urinary aglycones of vitamin K1 (phylloquinone) in man. Biochem Med 1980; 24: 250-267.
  • 58 Watanabe M. et al. Ubiquinone and related compounds. XXVI. The urinary metabolites of phylloquinone and alpha-tocopherol. Chem Pharm Bull (To kyo) 1974; 22: 176-182.
  • 59 Imada I. et al. Metabolism of ubiquinone-7. Biochemistry 1970; 09: 2870-2878.
  • 60 Losito R. et al. Metabolic studies of vitamin K1-14C and menadione-14C in the normal and hepatectomized rats. Thromb Diath Haemorrh 1968; 19: 383-388.
  • 61 Harrington DJ. et al. Determination of the urinary aglycone metabolites of vitamin K by HPLC with redox-mode electrochemical detection. J Lipid Res 2005; 46: 1053-1060.
  • 62 Harrington DJ. et al. Excretion of the urinary 5Cand 7C-aglycone metabolites of vitamin K by young adults responds to changes in dietary phylloquinone and dihydrophylloquinone intakes. J Nutr 2007; 137: 1763-1768.
  • 63 Sontag TJ, Parker RS. Cytochrome P450 omega-hydroxylase pathway of tocopherol catabolism. Novel mechanism of regulation of vitamin E status. J Biol Chem 2002; 277: 25290-25296.
  • 64 Landes N. et al. Vitamin E activates gene expression via the pregnane X receptor. Biochem Pharmacol 2003; 65: 269-273.
  • 65 Traber MG. et al. Vitamin E revisited: do new data validate benefits for chronic disease prevention?. Curr Opin Lipidol 2008; 19: 30-38.
  • 66 Landes N. et al. Homologous metabolic and gene activating routes for vitamins E and K. Mol Aspects Med 2003; 24: 337-344.
  • 67 Tabb MM. et al. Vitamin K2 regulation of bone homeostasis is mediated by the steroid and xenobiotic receptor SXR. J Biol Chem 2003; 278: 43919-43927.
  • 68 Astedt B. Antenatal drugs affecting vitamin K status of the fetus and the newborn. Semin Thromb Hemost 1995; 21: 364-370.
  • 69 Thierry MJ, Suttie JW. Effect of warfarin and the chloro analog of vitamin K1 on phylloquinone metabolism. Arch Biochem Biophys 1971; 147: 430-435.
  • 70 Konishi T. et al. Intracellular and intramitochondrial distribution of vitamin K: biochemical and electron microscopic radioautographic study. Chem Pharm Bull (To kyo) 1973; 21: 2479-2487.
  • 71 Ross PJ. et al. A fibroblast cell culture model to study vitamin K metabolism and the inhibition of vitamin K epoxide reductase by known and suspected antagonists. Br J Haematol 1991; 77: 195-200.
  • 72 Gundberg CM. et al. Vitamin K status and bone health: an analysis of methods for determination of undercarboxylated osteocalcin. J Clin Endocrinol Metab 1998; 83: 3258-3266.
  • 73 Will BH, Suttie JW. Comparative metabolism of phylloquinone and menaquinone-9 in rat liver. J Nutr 1992; 122: 953-958.
  • 74 Haffa A. et al. Diet- or warfarin-induced vitamin K insufficiency elevates circulating undercarboxylated osteocalcin without altering skeletal status in growing female rats. J Bone Miner Res 2000; 15: 872-878.
  • 75 Duello TJ, Matschiner JT. Characterization of vitamin K from human liver. J Nutr 1972; 102: 331-336.
  • 76 Booth SL. et al. Effects of a hydrogenated form of vitamin K on bone formation and resorption. Am J Clin Nutr 2001; 74: 783-790.
  • 77 Ferland G. et al. Dietary induced subclinical vitamin K deficiency in normal human subjects. J Clin Invest 1993; 91: 1761-1768.
  • 78 Matschiner JT. et al. Isolation and characterization of a new metabolite of phylloquinone in the rat. Biochim Biophys Acta 1970; 201: 309-315.
  • 79 Price PA. et al. Wa rfarin causes rapid calcification of the elastic lamellae in rat arteries and heart valves. Arterioscler Thromb Va sc Biol 1998; 18: 1400-1407.
  • 80 Wallin R. et al. Matrix Gla protein synthesis and gamma-carboxylation in the aortic vessel wall and proliferating vascular smooth muscle cells: a cell system which resembles the system in bone cells. Thromb Haemost 1999; 82: 1764-1767.
  • 81 Schurgers LJ. et al. Regression of warfarin-induced medial elastocalcinosis by high intake of vitamin K in rats. Blood 2007; 109: 2823-2831.
  • 82 Taggart WV, Matschiner JT. Metabolism of menadione-6,7-3H in the rat. Biochemistry 1969; 08: 1141-1146.
  • 83 Schurgers LJ. et al. Effect of vitamin K intake on the stability of oral anticoagulant treatment: dose-response relationships in healthy subjects. Blood 2004; 104: 2682-2689.
  • 84 Sconce E. et al. Patients with unstable control have a poorer dietary intake of vitamin K compared to patients with stable control of anticoagulation. Thromb Haemost 2005; 93: 872-875.
  • 85 Sconce E. et al. Vitamin K supplementation can improve stability of anticoagulation for patients with unexplained variability in response to warfarin. Blood 2007; 109: 2419-2423.
  • 86 Rombouts EK. et al. Daily vitamin K supplementation improves anticoagulant stability. J Thromb Haemost 2007; 05: 2043-2048.
  • 87 Stafford DW. et al. Vitamin K supplementation during oral anticoagulation: cautions. Blood 2007; 109: 3607.
  • 88 Sconce E. et al. Vitamin K supplementation during oral anticoagulation: no real cause for concern. Blood 2007; 109: 3607-3608.
  • 89 Schurgers LJ. et al. Oral anticoagulant treatment: friend or foe in cardiovascular disease. Blood 2004; 104: 3231-3232.
  • 90 Matschiner JT, Doisy EA. Bioassay of vitamin K in chicks. J Nutr 1966; 90: 97-100.
  • 91 Matschiner JT, Taggart WV. Bioassay of vitamin K by intracardial injection in deficient adult male rats. J Nutr 1968; 94: 57-59.
  • 92 Buitenhuis HC. et al. Comparison of the vitamins K1, K2 and K3 as cofactors for the hepatic vitamin K-dependent carboxylase. Biochim Biophys Acta 1990; 1034: 170-175.
  • 93 Hodges SJ. et al. Depressed levels of circulating menaquinones in patients with osteoporotic fractures of the spine and femoral neck. Bone 1991; 12: 387-389.
  • 94 Orimo H. et al. Clinical evaluation of menatetrenone in the treatment of involutional osteoporosis-a double blind multicenter comparative study with 1α hydroxy vitamin D3 . J Bone Miner Res 1992; (Suppl. 01) 07: S122.
  • 95 Akiyama Y. et al. Effects of menatetrenone on bone loss induced by ovariectomy in rats. Jpn J Pharmacol 1993; 62: 145-153.
  • 96 Hara K. et al. Effects of menatetrenone on prednisolone-induced bone loss in rats. Bone 1993; 14: 813-818.
  • 97 Koshihara Y. et al. Vitamin K2 (menatetrenone) inhibits prostaglandin synthesis in cultured human osteoblast-like periosteal cells by inhibiting prostaglandin H synthase activity. Biochem Pharmacol 1993; 46: 1355-1362.
  • 98 Akiyama Y. et al. Effect of vitamin K2 (menatetrenone) on osteoclast-like cell formation in mouse bone marrow cultures. Eur J Pharmacol 1994; 263: 181-185.
  • 99 Hara K. et al. The inhibitory effect of vitamin K2 (menatetrenone) on bone resorption may be related to its side chain. Bone 1995; 16: 179-184.
  • 100 Nanke Y. et al. Geranylgeranylacetone inhibits formation and function of human osteoclasts and prevents bone loss in tail-suspended rats and ovariectomized rats. Calcif Tissue Int 2005; 77: 376-385.
  • 101 Kearns AE. et al. Receptor activator of nuclear factor kappaB ligand and osteoprotegerin regulation of bone remodelling in health and disease. Endocr Rev 2008; 29: 155-192.
  • 102 Hiruma Y. et al. Vitamin K2 and geranylgeraniol, its side chain component, inhibited osteoclast formation in a different manner. Biochem Biophys Res Commun 2004; 314: 24-30.
  • 103 Koshihara Y. et al. Vitamin K stimulates osteoblas-togenesis and inhibits osteoclastogenesis in human bone marrow cell culture. J Endocrinol 2003; 176: 339-348.
  • 104 Kameda T. et al. Vitamin K2 inhibits osteoclastic bone resorption by inducing osteoclast apoptosis. Biochem Biophys Res Commun 1996; 220: 515-519.
  • 105 Sakai I. et al. Novel role of vitamin K2: a potent in-ducer of differentiation of various human myeloid leukaemia cell lines. Biochem Biophys Res Commun 1994; 205: 1305-1310.
  • 106 Yaguchi M. et al. Vitamin K2 and its derivatives induce apoptosis in leukaemia cells and enhance the effect of all-trans retinoic acid. Leukemia 1997; 11: 779-787.
  • 107 Masuda Y. et al. Geranylgeraniol potently induces caspase-3-like activity during apoptosis in human leukaemia U937 cells. Biochem Biophys Res Commun 1997; 234: 641-645.
  • 108 Tokita H. et al. Vitamin K2-induced antitumor effects via cell-cycle arrest and apoptosis in gastric cancer cell lines. Int J Mol Med 2006; 17: 235-243.
  • 109 Ogawa M. et al. Vitamins K2, K3 and K5 exert antitumor effects on established colorectal cancer in mice by inducing apoptotic death of tumor cells. Int J Oncol 2007; 31: 323-331.
  • 110 Habu D. et al. Role of vitamin K2 in the development of hepatocellular carcinoma in women with viral cirrhosis of the liver. J Am Med Assoc 2004; 292: 358-361.
  • 111 Mizuta T. et al. The effect of Menatetrenone, a vitamin K2 analog, on disease recurrence and survival in patients with hepatocellular carcinoma after curative treatment: a pilot study. Cancer 2006; 106: 867-872.
  • 112 Kuriyama S. et al. Vitamins K2, K3 and K5 exert in vivo antitumor effects on hepatocellular carcinoma by regulating the expression of G1 phase-related cell cycle molecules. Int J Oncol 2005; 27: 505-511.
  • 113 Ozaki I. et al. Menatetrenone, a vitamin K2 analogue, inhibits hepatocellular carcinoma cell growth by suppressing cyclin D1 expression through inhibition of nuclear factor kappaB activation. Clin Cancer Res 2007; 13: 2236-2245.
  • 114 Hoshi K. et al. Nuclear vitamin K2 binding protein in human osteoblasts: homologue to glyceraldehyde-3-phosphate dehydrogenase. Biochem Pharmacol 1999; 58: 1631-1638.
  • 115 Ichikawa T. et al. Steroid and xenobiotic receptor SXR mediates vitamin K2-activated transcription of extracellular matrix-related genes and collagen accumulation in osteoblastic cells. J Biol Chem 2006; 281: 16927-16934.
  • 116 Igarashi M. et al. Vitamin K induces osteoblast differentiation through pregnane X receptor-mediated transcriptional control of the Msx2 gene. Mol Cell Biol 2007; 27: 7947-7954.
  • 117 Ichikawa T. et al. Vitamin K2 induces phosphorylation of protein kinase A and expression of novel target genes in osteoblastic cells. J Mol Endocrinol 2007; 39: 239-247.
  • 118 Ronden JE. et al. Modulation of arterial thrombosis tendency in rats by vitamin K and its side chains. Atherosclerosis 1997; 132: 61-67.
  • 119 Reddi K. et al. Interleukin 6 production by lipo-polysaccharide-stimulated human fibroblasts is potently inhibited by naphthoquinone (vitamin K) compounds. Cytokine 1995; 03: 287-290.
  • 120 Ohsaki Y. et al. Vitamin K suppresses lipopolysaccharide-induced inflammation in the rat. Biosci Biotechnol Biochem 2006; 70: 926-932.
  • 121 Shea MK. et al. Vitamin K and vitamin D status: associations with inflammatory markers in the Framingham Offspring Study. Am J Epidemiol 2008; 167: 313-320.
  • 122 Li J. et al. Novel role of vitamin K in preventing oxidative injury to developing oligodendrocytes and neurons. J Neurosci 2003; 23: 5816-5826.
  • 123 Mukai K. et al. Kinetic study of free-radical-scavenging action of biological hydroquinones (reduced forms of ubiquinone, vitamin K and tocopherol quinone) in solution. Biochim Biophys Acta 1993; 1157: 313-317.
  • 124 Vervoort LMT. et al. The potent antioxidant activity of the vitamin K cycle in microsomal lipid peroxidation. Biochem Pharmacol 1997; 54: 871-876.
  • 125 Lev M, Milford AF. Effect of vitamin K depletion and restoration on sphingolipid metabolism in Bacte-roides melaninogenicus.. . J Lipid Res 1972; 13: 364-370.
  • 126 Sundaram KS, Lev M. Warfarin administration reduces synthesis of sulfatides and other sphingolipids in mouse brain. J Lipid Res 1988; 29: 1475-1479.
  • 127 Sundaram KS, Lev M. Regulation of sulfotransfe-rase activity by vitamin K in mouse brain. Arch Biochem Biophys 1990; 277: 109-113.
  • 128 Sundaram KS. et al. Vitamin K status influences brain sulfatide metabolism in young mice and rats. J Nutr 1996; 126: 2746-2751.
  • 129 Carrié I. et al. Menaquinone-4 concentration is correlated with sphingolipid concentrations in rat brain. J Nutr 2004; 134: 167-172.
  • 130 Cocchetto DM. et al. Behavioral perturbations in the vitamin K-deficient rat. Physiol Behav 1985; 34: 727-734.
  • 131 Thomas DDH. et al. Exocrine pancreatic secretion of phospholipid, menaquinone-4, and caveolin-1 in vivo. Biochem Biophys Res Commun 2004; 319: 974-979.
  • 132 Stenberg LM. et al. Synthesis of gamma-carboxy-lated polypeptides by alpha-cells of the pancreatic islets. Biochem Biophys Res Commun 2001; 283: 454-459.