Effects of ovarian steroid hormones and thyroxine on calcitonin secretion in pregnant rats

L. U. Chien-Chen, Shiow Chwen Tsai, Shyi W U Wang, Ching Lin Tsai, Chin Pang Lau, Hsi Chang Shih, Yen Hao Chen, Y. U Chung Chiao, Charlie Liaw, Paulus S. Wang

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


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, preand post-Cada 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 calciuminduced 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.

Original languageEnglish (US)
Pages (from-to)E246-E252
JournalAmerican Journal of Physiology - Endocrinology and Metabolism
Issue number2 PART 1
StatePublished - Feb 1 1998


  • Estradiol
  • Progesterone

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Biochemistry


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