Expression of Cyclooxygenase-1 and -2 in Ovine Endometrium During the Estrous Cycle and Early Pregnancy

• Published in: Endocrinology (Philadelphia) 1997-05, Vol.138 (5), p.2163-2171
• Main Authors: Charpigny, Gilles, Reinaud, Pierrette, Tamby, Jean-Philippe, Créminon, Christophe, Martal, Jacques, Maclouf, Jacques, Guillomot, Michel
• Format: Article
• Language: English
• Subjects: 17β-Estradiol; Cyclooxygenase-1; Cyclooxygenase-2; Endometrium; Epithelium; Estrus cycle; Ovariectomy; Pregnancy; Progesterone; Sex hormones; Steroid hormones; Stromal cells; Uterus
• ISSN: 0013-7227; 1945-7170
• DOI: 10.1210/endo.138.5.5148

Abstract In this study we investigated the expression of the two cyclooxygenases, cox-1 and -2, in sheep uterine tissues during the estrous cycle and early pregnancy. We identified the cox-2 isoform in the ovine uterus by Western blot and demonstrated that the two cyclooxygenases exhibited different patterns of expression. Cox-1 was expressed at steady state levels in the endometrium during the estrous cycle and comparable stages of pregnancy. In contrast, cox-2 was highly and transiently expressed from days 12–15 of the estrous cycle and declined thereafter to undetectable levels. Endometrium from early pregnant ewes showed a similar pattern of cox-2 expression, although there was a slower decrease beyond day 15. Immunohistochemical studies demonstrated that cox-1 was localized in both epithelial and stromal cells, whereas cox-2 was localized solely in the luminal epithelium and to a lesser extent in the superficial glands. Treatment of ovariectomized ewes with steroids indicated that expression of cox-1 remained at constant levels whatever the treatment. In contrast, endometrial cox-2 was highly induced by a 10-day progesterone treatment. Estradiol slightly increased cox-2 expression but only after progesterone priming. Collectively these results suggest that the developing ability of the uterus to synthesize PGs is due to the induction of cox-2.