Circulating osteocalcin during oral anticoagulant therapy.

In this paper we present the following observations: 1) In sheep vitamin K-antagonists like phenprocoumon induce a decrease of the serum levels of osteocalcin (bone Gla-protein) and of the affinity of the circulating osteocalcin for hydroxyapatite. 2) In sheep vitamin K counteracts the effect of phenprocoumon on the blood coagulation system, but not that on the osteocalcin production. 3) In human subjects vitamin K-antagonists also lead to decreased levels of serum osteocalcin and a low affinity of the protein for hydroxyapatite. 4) These two variables reached steady-state levels within 24 h after the start of oral anticoagulant treatment and--at continuation of the therapy--they remained low for at least several years.