title: Assessment of vitamin K status in human subjects administered "minidose" warfarin.
abstract: Vitamin K is required to convert specific glutamyl residues in a limited number of proteins to gamma-carboxyglutamyl residues. The response of various measures of vitamin K insufficiency to the administration of 1 mg/d of the vitamin K antagonist warfarin was studied in two groups of nine older (55-75 y) or younger (20-28 y) subjects. The most consistent and extensive alteration was an increase in the concentration of serum under-gamma-carboxylated osteocalcin followed by increased immunochemical detection of plasma under-gamma-carboxylated prothrombin (PIVKA-II), and by a decreased urinary excretion of gamma-carboxyglutamic acid. Plasma concentrations of prothrombin were altered by this treatment but prothrombin times, factor VII activity, prothrombin F-1 x 2 concentrations, and a less sensitive assay for under-gamma-carboxylated prothrombine were not. The concentration of serum under-gamma-carboxylated osteocalcin was lower when subjects consumed 1 mg vitamin K/d than when they consumed their normal diet.
authors.affiliation: Department of Nutritional Sciences, College of Agricultural and Life Sciences, University of Wisconsin-Madison 53706, USA.
authors.forename: A U
authors.initials: AU
authors.lastname: Bach
authors.forename: S A
authors.initials: SA
authors.lastname: Anderson
authors.forename: A L
authors.initials: AL
authors.lastname: Foley
authors.forename: E C
authors.initials: EC
authors.lastname: Williams
authors.forename: J W
authors.initials: JW
authors.lastname: Suttie
mesh_terms: D015055:1-Carboxyglutamic Acid / Q000652:urine; D000328:Adult; D000368:Aged; D000925:Anticoagulants / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood; D011516:Prothrombin / Q000032:analysis; D013927:Thrombosis / Q000453:epidemiology / Q000517:prevention & control; D014812:Vitamin K / Q000097:blood*; D010837:Vitamin K 1 / Q000031:analogs & derivatives / Q000097:blood; D014859:Warfarin / Q000494:pharmacology*
chemical_list: D000925:Anticoagulants; D015675:Osteocalcin; D014812:Vitamin K; C016186:vitamin K1 oxide; D015055:1-Carboxyglutamic Acid; D014859:Warfarin; D010837:Vitamin K 1; D011516:Prothrombin