Exogenous glucocorticoids affect in different way the various phases of bone formation in postmenopausal patients.

To determine the effect of glucocorticoid excess on the most important circulating markers of bone formation in postmenopausal treated patients. METHODS: The study included 15 postmenopausal women taking glucocorticoids for various medical conditions and two groups of 30 healthy premenopausal and 28 age-matched postmenopausal women as controls. Osteoblastic activity was assessed by measuring both serum levels of osteocalcin (BGP) (N-tact Osteo SP, Incstar Co.) and the bone-specific isoenzyme of alkaline phosphatase (BAP) (Alkphase-B, Metra Biosystems). RESULTS: The mean values of serum BGP found in patients taking steroids were significantly reduced as compared to those found in both fertile and postmenopausal women (p < 0.0001). The mean serum levels of BAP were significantly increased in treated patients as compared to premenopausal women (p < 0.0001), while no significant difference was found between patients and age-matched postmenopausal women. Similar results were also obtained when individual values of both serum BAP and BGP were expressed as standard units in comparison to values obtained in fertile subjects (T-score) or postmenopausal subjects (Z-score). CONCLUSIONS: Steroid therapy in postmenopausal patients differentially affects the various phases of bone formation. Measurement of serum BGP may represent a reliable parameter for monitoring bone formation in postmenopausal treated patien