[Bone mineral content in premenopausal women treated with gonadotropin-releasing hormone analogue]

To assess bone metabolism during treatment with gonadotropin-releasing hormone analogue (GnRHa), serum osteocalcin (BGP), alkaline phosphatase (ALP), parathyroid hormone (PTH), calcitonin (CT), calcium (Ca) and phosphorus (P) were determined before and after 6 months of GnRHa treatment in 15 premenopausal women with clinically diagnosed endometriosis. The bone mineral content (BMC) of the lumbar spine (L3) was measured by single energy quantitative computed tomography in 9 women, and in 6 of these 9 women microdensitometry was performed simultaneously during the treatment. BMC decreased significantly to 92.5 +/- 6.8% (mean +/- SD) of the pretreatment value after 6 months of treatment. On the other hand, microdensitometry revealed no significant change during treatment. Serum BGP and ALP were significantly higher after 6 months of treatment than before treatment, indicating an increase in bone formation. These data indicate that the GnRHa treatment induces an increase in bone turnover and a significant bone loss.