[Modifications in the urinary excretion of gamma-carboxyglutamic acid induced by vitamin K]

To evaluate urinary GLA excretion, a marker of vitamin K metabolism, the effect of an oral calcium load was studied in 8 volunteers under three conditions: (1) after 1.5 g elementary calcium (calcium carbonate), (2) after 1.5 g calcium (Ossopan, a preparation containing 1 mg osteocalcin per g) and (3) after 1.5 g calcium but with pretreatment of 10 mg vitamin K1 orally for 3 days. No differences in blood calcium, osteocalcin concentration of calciuria were observed. However, GLA excretion was significantly higher with Ossopan or after pretreatment with vitamin K1.