Body J J, Struelens M, Borkowski A, Mandart G
Service de Médecine, Institut J. Bordet, l'Université Libre de Bruxelles, Belgium.
J Clin Endocrinol Metab. 1989 Jan;68(1):223-6. doi: 10.1210/jcem-68-1-223.
The protective action of estrogens on bone mass may be mediated by an increase in calcitonin (CT) secretion. We reevaluated this hypothesis using a method for measuring CT in extracts of serum that allows sensitive specific measurement of CT monomer. We studied seven healthy postmenopausal women before and on the 7th and 28th days of each of three 4-week treatment periods: estrogen (estradiol valerate; 2 mg/day), calcium supplement (1500 mg/day), and estrogen plus calcium; the three cycles were separated by intervals of 4 weeks. Serum extractable CT (exCT) levels were measured before and after a short calcium stimulation test (2 mg Ca/kg in 5 min) to assess the C-cell secretory response on each day. Estrogen had the expected biological effects, decreasing (P less than 0.05) serum gonadotropin concentrations and fasting or 24-h urinary calcium excretion. The calcium supplement caused a significant increase in 24-h urinary calcium excretion. However, there was no increase in basal or stimulated serum exCT levels during any of the three cycles. On the contrary, basal serum exCT concentrations decreased slightly but significantly during estrogen treatment from 1.9 +/- 0.5 (+/- SE) to 1.5 +/- 0.4 ng/L on day 7 and 1.2 +/- 0.2 ng/L on day 28 (P less than 0.05). This decrease in basal exCT levels did not occur during the combined estrogen and calcium administration period, probably because the slight decrease in serum calcium induced by estrogen did not occur during combined estrogen and calcium administration. In summary, estrogens do not stimulate CT secretion; variations in serum exCT levels appear to be related to the changes in bone metabolism induced by estrogens.
雌激素对骨量的保护作用可能是通过降钙素（CT）分泌增加来介导的。我们使用一种测量血清提取物中CT的方法重新评估了这一假说，该方法能够灵敏且特异的测量CT单体。我们研究了7名健康的绝经后女性，在三个为期4周的治疗周期中，分别于每个周期的第1天、第7天和第28天进行研究：雌激素（戊酸雌二醇；2mg/天）、补钙（1500mg/天）以及雌激素加钙；三个周期之间间隔4周。在短时间钙刺激试验（5分钟内给予2mg钙/kg）前后测量血清可提取CT（exCT）水平，以评估每天的C细胞分泌反应。雌激素产生了预期的生物学效应，降低了（P<0.05）血清促性腺激素浓度以及空腹或24小时尿钙排泄量。补钙导致24小时尿钙排泄量显著增加。然而，在三个周期中的任何一个周期，基础或刺激后的血清exCT水平均未升高。相反，在雌激素治疗期间，基础血清exCT浓度略有下降但显著，从第7天的1.9±0.5（±SE）降至1.5±0.4ng/L，第28天降至1.2±0.2ng/L（P<0.05）。在雌激素和钙联合给药期间未出现基础exCT水平的下降，可能是因为雌激素和钙联合给药期间未出现雌激素诱导的血清钙轻微下降。总之，雌激素不会刺激CT分泌；血清exCT水平的变化似乎与雌激素诱导的骨代谢变化有关。
