title: Depressed levels of circulating menaquinones in patients with osteoporotic fractures of the spine and femoral neck.
abstract: Vitamin K1 functions in the conversion of glutamate residues, present in certain bone peptides, into the putatively active gamma-carboxyglutamate form. We have shown previously that the circulating levels of vitamin K1 are depressed in osteoporotic patients. However, it is known that menaquinones (vitamin K2:MK) may be more effective than vitamin K1 in this conversion of the inactive to active form of glutamate residues. A procedure for measuring such menaquinones has now demonstrated a marked deficiency of MK-7 and MK-8 in patients with osteoporotic fractures. It is suggested that estimates of circulating levels of K1, MK-7, and MK-8 might provide a biochemical risk marker of osteoporotic fractures.
authors.affiliation: Unit of Cellular Pharmacology and Toxicology, Robens Institute, University of Surrey, Guildford, U.K.
authors.forename: S J
authors.initials: SJ
authors.lastname: Hodges
authors.forename: M J
authors.initials: MJ
authors.lastname: Pilkington
authors.forename: T C
authors.initials: TC
authors.lastname: Stamp
authors.forename: A
authors.initials: A
authors.lastname: Catterall
authors.forename: M J
authors.initials: MJ
authors.lastname: Shearer
authors.forename: L
authors.initials: L
authors.lastname: Bitensky
authors.forename: J
authors.initials: J
authors.lastname: Chayen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005265:Femoral Neck Fractures / Q000097:blood* / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications*; D016103:Spinal Fractures / Q000097:blood* / Q000209:etiology; D014812:Vitamin K / Q000031:analogs & derivatives* / Q000097:blood; D024482:Vitamin K 2 / Q000031:analogs & derivatives*
chemical_list: D024482:Vitamin K 2; D014812:Vitamin K; C024223:vitamin MK 8; C062629:menaquinone 7