The in vivo effects of oral anticoagulants in man: comparison between liver and non-hepatic tissues.
The in vivo effects of oral anticoagulant therapy with 4-hydroxycoumarins on various vitamin K-dependent enzyme systems in man were compared. In hepatic microsomes obtained from donors who has been treated with 4-hydroxycoumarins for more than 6 months, the vitamin K 2,3 epoxide reductase activity and the DTT-dependent vitamin K quinone reductase activity were diminished to 35% and 20% of the corresponding normal values. In the non-hepatic tissues, only a small decrease in vitamin K 2,3 epoxide reductase activity could be demonstrated, while no differences were found in the vitamin K quinone reductase activities. In none of the tissues a significant increase of noncarboxylated precursor proteins was observed, whereas also vitamin K hydroquinone-dependent carboxylase activities seemed to be unaffected by the anticoagulant treatment.
de Boer-van den Berg
M
M
Department of Biochemistry, University of Limburg, Maastricht, The Netherlands.
Thijssen
H H
HH
Vermeer
C
C
D015110:4-Hydroxycoumarins / Q000008:administration & dosage / Q000494:pharmacology; D000284:Administration, Oral; D000925:Anticoagulants / Q000008:administration & dosage / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D006801:Humans; D008861:Microsomes / Q000187:drug effects / Q000378:metabolism; D008862:Microsomes, Liver / Q000187:drug effects* / Q000378:metabolism; D009928:Organ Specificity; D015675:Osteocalcin; D014812:Vitamin K / Q000378:metabolism
D015110:4-Hydroxycoumarins; D000925:Anticoagulants; D002135:Calcium-Binding Proteins; D015675:Osteocalcin; D014812:Vitamin K