A study on urinary free gamma-carboxyglutamic acid in patients with idiopathic urinary calcium stone]

Currently, urinary excretion of free gamma-carboxyglutamic acid (gamma-gla.), a terminal amino acid degraded from gamma-gla. containing protein including bone Gla. Estimated to be a more specific marker for bone metabolism and useful clinically rather than urinary excretion of hydroxyproline. In addition, serum levels of BGP have proved to be a significantly valuable indicator for bone metabolism, especially for process of bone formation, in recent studies. Therefore, we measured these parameters in 40 patients with idiopathic urinary calcium (Ca) stone and investigated bone metabolism in those patients. However, in majority of cases studied, urinary levels of gamma-gla. as well as that of hydroxyproline proved to be definite difference from that in healthy subjects (n = 12) and failed to suggest the presence of abnormality in bone turnover in the background of stone formation. Urinary excretion of hydroxyproline were 6.68 +/- 3.89 micrograms/mg.Cr in the patients and 6.95 +/- 3.08 micrograms/mg.Cr in healthy subjects. Urinary excretion of gamma-gla were 55.0 +/- 15.8 nmol/mg.Cr in the patients and 47.2 +/- 7.3 nmol/mg.Cr in healthy subjects.