HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 73/2/343    most recent biolreprod.104.037820v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Wu, W. X. Articles by Nathanielsz, P. W. Search for Related Content PubMed PubMed Citation Articles by Wu, W. X. Articles by Nathanielsz, P. W. Agricola Articles by Wu, W. X. Articles by Nathanielsz, P. W.

Sufficient Progesterone-Priming Prior to Estradiol Stimulation Is Required for Optimal Induction of the Cervical Prostaglandin System in Pregnant Sheep at 0.7 Gestations¹

Department of Obstetrics and Gynecology,³ Wake Forest University SOM, Winston-Salem, North Carolina 27157 Department of Obstetrics and Gynecology,⁴ University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104 Department of Obstetrics and Gynecology,⁵ University of Texas Health Sciences Center, San Antonio, Texas 78229

The purposes of this study were to determine the separate and interactive functions of progesterone and estradiol in regulating the cervical prostaglandin (PG) system in pregnant sheep at 0.7 gestations. At 106–108 days of gestational age (dGA), ewes were treated with vehicle for 14 days (n = 5) or vehicle for 12 days followed by estradiol 5 mg twice a day, intramuscularly for 2 days (n = 5) or progesterone 100 mg, twice a day, intramuscularly for 14 days (n = 5) or progesterone 100 mg twice a day, intramuscularly for 10 days and then 2 days vehicle followed by estradiol 5 mg twice a day intramuscularly for 2 days (n = 5). At 121–123 dGA, cervical tissues were obtained under halothane anesthesia. Cervical RNA and protein were extracted and analyzed for prostaglandin-endoperoxide synthase 2 (COX2), two PGE₂ receptors, PTGER2 and PTGER4, and estrogen receptor alpha (ESR1) by Northern and Western blot analysis. Immunocytochemistry and in situ hybridization were applied to localize cellular distribution of COX2, PTGER2, and PTGER4 in the cervix. Data were analyzed by ANOVA. COX2 and PTGER4 mRNAs and proteins were increased (P < 0.05) in ewes treated with combined estradiol and progesterone but not in ewes treated with estradiol or progesterone alone compared with controls. ESR1 mRNA was increased in ewes treated with progesterone and estradiol plus progesterone. In contrast, PTGER2 mRNA and protein remained the same after all treatments. COX2 mRNA and protein were localized only in cervical glandular epithelial cells, whereas PTGER2 and PTGER4 were localized in both cervical glandular epithelial and smooth muscle cells. In conclusion, these data suggest that additional progesterone priming at 0.7 gestations synergizes with estradiol to induce cervical COX2, PTGER4, and ESR1 and support our hypothesis that stimulation of the cervical PG system by estradiol is optimized by sufficient progesterone priming in the pregnant sheep cervix.

cervix, estradiol, parturition, PG, progesterone, sheep

² Correspondence: Wen Xuan Wu, Department of Obstetrics and Gynecology, Wake Forest University, Baptist Medical Center, Winston-Salem, NC 27157. FAX: 336 716 6937; wenwu{at}wfubmc.edu