DETECTION AND MEASUREMENT OF VITAMIN-K(1) AND VITAMIN-K(2) IN HUMAN CORTICAL AND TRABECULAR BONE

Vitamin K plays an essential role in the gamma carboxYlation of the gl a-containing proteins of bone matrix, such as osteocalcin. We have mea sured the concentration of vitamin K1 (VK) and of the menaquinones MK- 6, MK-7, and MK-8, the three major vitamin K2 moieties, in trabecular and cortical bone taken from the femoral neck of patients undergoing h ip replacement. Both bone compartments were found to contain large amo unts of VK, MK-6, MK-7, and MK-8. Concentrations were as high as those reported for the liver, the major storage organ for vitamin K. Furthe r research is required to examine the association between vitamin K in bone and the gamma carboxylation of vitamin K-dependent bone proteins .