Tags

Type your tag names separated by a space and hit enter

Vitamin K metabolism and nutriture.
Blood Rev 1992; 6(2):92-104BR

Abstract

Vitamin K functions as a co-factor for the post-translational carboxylation of specific glutamate residues to gamma-carboxyglutamate (Gla) residues in several blood coagulation factors (II, VII, IX and X) and coagulation inhibitors (proteins C and S) in the liver; as well as a variety of extrahepatic proteins such as the bone protein osteocalcin. This review outlines some recent advances in our understanding of the metabolism of vitamin K and its role in human nutriture. The introduction of new methodologies to measure the low endogenous tissue concentrations of K vitamins and circulating plasma levels of des-gamma-carboxyprothrombin (PIVKA-II) have provided correspondingly more refined indices for the assessment of human vitamin K status. The assays for vitamin K have also been used to study the sources, intestinal absorption, plasma transport, storage and transplacental transfer of K vitamins and the importance of phylloquinone (vitamin K1) versus menaquinones (vitamins K2) to human needs. The ability to biochemically monitor subclinical vitamin K deficiency has reaffirmed the precarious vitamin K status of the newborn and led to an increased appreciation of the risk factors leading to haemorrhagic disease of the newborn and how this may be prevented. Biochemical studies are leading to an increased knowledge of the mode of action of traditional coumarin anticoagulants and how some unrelated compounds (e.g. antibiotics) may also antagonize vitamin K and cause bleeding. There is also an awareness of the possible deleterious effects of vitamin K antagonism or deficiency on non-hepatic Gla-proteins which may play some subtle role in calcium homeostasis.

Authors+Show Affiliations

Haematology Department, Guy's Hospital, London, UK.

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

1633511

Citation

Shearer, M J.. "Vitamin K Metabolism and Nutriture." Blood Reviews, vol. 6, no. 2, 1992, pp. 92-104.
Shearer MJ. Vitamin K metabolism and nutriture. Blood Rev. 1992;6(2):92-104.
Shearer, M. J. (1992). Vitamin K metabolism and nutriture. Blood Reviews, 6(2), pp. 92-104.
Shearer MJ. Vitamin K Metabolism and Nutriture. Blood Rev. 1992;6(2):92-104. PubMed PMID: 1633511.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Vitamin K metabolism and nutriture. A1 - Shearer,M J, PY - 1992/6/1/pubmed PY - 1992/6/1/medline PY - 1992/6/1/entrez SP - 92 EP - 104 JF - Blood reviews JO - Blood Rev. VL - 6 IS - 2 N2 - Vitamin K functions as a co-factor for the post-translational carboxylation of specific glutamate residues to gamma-carboxyglutamate (Gla) residues in several blood coagulation factors (II, VII, IX and X) and coagulation inhibitors (proteins C and S) in the liver; as well as a variety of extrahepatic proteins such as the bone protein osteocalcin. This review outlines some recent advances in our understanding of the metabolism of vitamin K and its role in human nutriture. The introduction of new methodologies to measure the low endogenous tissue concentrations of K vitamins and circulating plasma levels of des-gamma-carboxyprothrombin (PIVKA-II) have provided correspondingly more refined indices for the assessment of human vitamin K status. The assays for vitamin K have also been used to study the sources, intestinal absorption, plasma transport, storage and transplacental transfer of K vitamins and the importance of phylloquinone (vitamin K1) versus menaquinones (vitamins K2) to human needs. The ability to biochemically monitor subclinical vitamin K deficiency has reaffirmed the precarious vitamin K status of the newborn and led to an increased appreciation of the risk factors leading to haemorrhagic disease of the newborn and how this may be prevented. Biochemical studies are leading to an increased knowledge of the mode of action of traditional coumarin anticoagulants and how some unrelated compounds (e.g. antibiotics) may also antagonize vitamin K and cause bleeding. There is also an awareness of the possible deleterious effects of vitamin K antagonism or deficiency on non-hepatic Gla-proteins which may play some subtle role in calcium homeostasis. SN - 0268-960X UR - https://www.unboundmedicine.com/medline/citation/1633511/Vitamin_K_metabolism_and_nutriture_ L2 - https://linkinghub.elsevier.com/retrieve/pii/0268-960X(92)90011-E DB - PRIME DP - Unbound Medicine ER -