Lu C C, Tsai S C, Wang S W, Tsai C L, Lau C P, Shih H C, Chen Y H, Chiao Y C, Liaw C, Wang P S
Department of Physiology, School of Life Science, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Am J Physiol. 1998 Feb;274(2):E246-52. doi: 10.1152/ajpendo.1998.274.2.E246.
In the present study, the roles of ovarian steroid hormones and thyroxine (T4) in regulating the secretion of calcitonin (CT) in pregnant rats were examined. The levels of plasma progesterone, pre- and post-CaCl2 plasma CT, and recovery time of plasma CT and calcium after calcium challenge were greatest in midterm pregnant rats. The levels of basal plasma progesterone, CT, calcium, and recovery time of plasma CT after calcium challenge were less in late pregnant rats, but basal plasma estradiol was highest in late pregnancy. The concentrations of plasma T4 were gradually decreased in rats during pregnancy. Regardless of the presence of estradiol, administration of progesterone in ovariectomized (Ovx) rats resulted in an increase of plasma T4 as well as the basal and calcium-induced secretion of CT. Administration of estradiol alone did not alter the CaCl2-induced levels but decreased the post-CaCl2 levels of plasma calcium in Ovx rats. The basal levels of plasma CT were decreased in Ovx rats treated with T4. These results suggest that the hypercalcitoninemia in midterm pregnant rats is due to an increased secretion of progesterone. Hypocalcitoninemia in late pregnant rats, however, is due in part to lower plasma calcium.
在本研究中，检测了卵巢甾体激素和甲状腺素（T4）在调节妊娠大鼠降钙素（CT）分泌中的作用。血浆孕酮水平、氯化钙注射前后血浆CT水平以及钙激发后血浆CT和钙的恢复时间在妊娠中期大鼠中最高。妊娠晚期大鼠的基础血浆孕酮、CT、钙水平以及钙激发后血浆CT的恢复时间较低，但基础血浆雌二醇在妊娠晚期最高。妊娠期间大鼠血浆T4浓度逐渐降低。无论雌二醇是否存在，对去卵巢（Ovx）大鼠给予孕酮都会导致血浆T4增加以及基础和钙诱导的CT分泌增加。单独给予雌二醇不会改变氯化钙诱导的水平，但会降低Ovx大鼠氯化钙注射后血浆钙水平。用T4处理的Ovx大鼠血浆CT基础水平降低。这些结果表明，妊娠中期大鼠的高降钙素血症是由于孕酮分泌增加所致。然而，妊娠晚期大鼠的降钙素血症部分是由于血浆钙水平较低。
