Stacey E, Korkia P, Hukkanen M V, Polak J M, Rutherford O M
Department of Physiology, Imperial College School of Medicine, London, United Kingdom.
J Clin Endocrinol Metab. 1998 Sep;83(9):3056-61. doi: 10.1210/jcem.83.9.5106.
Amenorrheic athletes have been likened to postmenopausal women, with low estrogen levels and osteopenia. It has been suggested that estrogen exerts its antiresorptive actions on bone via a nitric oxide (NO)-dependent mechanism. This study investigated whether the mechanism of bone loss in amenorrheic athletes is similar to that of postmenopausal women with reduced NO levels and high bone turnover. Eleven amenorrheic athletes, 15 eumenorrheic athletes, and 10 sedentary controls were studied. Spine and hip bone mineral density was measured using dual-energy x-ray absorptiometry. Bone turnover was assessed by biochemical markers of formation (osteocalcin and bone-specific alkaline phosphatase) and resorption (deoxypyridinoline). NO metabolites were measured from 24-h urine samples using a chemiluminescence assay. Spine, but not hip, bone mineral density was reduced in the amenorrheic group, compared with the eumenorrheic (P = 0.0001) and control (P = 0.04) groups. Osteocalcin, bone-specific alkaline phosphatase, and deoxypyridinoline were similar in all groups. NO metabolites were lower in the amenorrheic group, compared with controls (P = 0.035), despite a higher dietary intake of nitrates. Unlike postmenopausal women, amenorrheic athletes do not have raised bone turnover but do have reduced NO metabolites and spinal osteopenia. The results show, however, that reduced NO production is a common denominator in both conditions and further support the importance of NO in estrogen-mediated protection of skeletal mass and strength.
闭经运动员被比作绝经后女性，雌激素水平低且患有骨质减少症。有人提出，雌激素通过一氧化氮（NO）依赖机制对骨骼发挥抗吸收作用。本研究调查了闭经运动员的骨质流失机制是否与NO水平降低和骨转换率高的绝经后女性相似。研究了11名闭经运动员、15名月经正常的运动员和10名久坐不动的对照者。使用双能X线吸收法测量脊柱和髋部骨密度。通过形成（骨钙素和骨特异性碱性磷酸酶）和吸收（脱氧吡啶啉）的生化标志物评估骨转换。使用化学发光分析法从24小时尿液样本中测量NO代谢物。与月经正常组（P = 0.0001）和对照组（P = 0.04）相比，闭经组脊柱骨密度降低，但髋部骨密度未降低。所有组的骨钙素、骨特异性碱性磷酸酶和脱氧吡啶啉相似。尽管硝酸盐饮食摄入量较高，但闭经组的NO代谢物低于对照组（P = 0.035）。与绝经后女性不同，闭经运动员的骨转换率没有升高，但NO代谢物减少，脊柱骨质减少。然而，结果表明，NO生成减少是两种情况的共同特征，并进一步支持了NO在雌激素介导的保护骨骼质量和强度中的重要性。
