[Calcium regulating hormone in the pathological changes of bone in rheumatoid arthritis]

To further elucidate the pathogenesis of calcium regulating hormones and bone Gla-protein (BGP) on the deteriorated bone changes in rheumatoid arthritis (RA), the degree of the appendicular bone atrophy, using microdensitometry method in patients with RA, and the concentrations of midchain mainly recognized parathyroid hormone (p-PTH1-84, intact parathyroid hormone (in-PTH1-84) and BGP in sera of patients with RA were measured. With concomitant progression in X-ray stage in RA, the levels of p-PTH1-84, in-PTH1-84, BGP, 25 (OH) D, and 24, 25 (OH)2D were significantly increased in sera of RA patients. The levels of 1,25 (OH)2D were not shown significant differences among RA patients classified by bone stage. These results might be concluded that the pathogenesis of the deteriorated bone change in RA seemed to be implicated in hyper-turnover bone presumably caused by the actions of parathyroid hormone and abnormal vitamin D metabolism.