Oxytocin receptor gene expression in the rat uterus during pregnancy and the estrous cycle and in response to gonadal steroid treatment
| Autor: | J Neculcea, Hans H. Zingg, A Larcher, Caterina Russo, A Arslan, Florence Rozen, Christophe Breton |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
medicine.medical_specialty
medicine.drug_class Uterus Oxytocin Endometrium Rats Sprague-Dawley Endocrinology Estrus Pregnancy Internal medicine Gene expression medicine Animals RNA Messenger Gonadal Steroid Hormones Progesterone Estrous cycle Binding Sites Estradiol Chemistry Myometrium Oxytocin receptor Rats medicine.anatomical_structure Gene Expression Regulation Receptors Oxytocin Estrogen Pregnancy Animal Female medicine.drug |
| Zdroj: | Endocrinology. 136:5350-5356 |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/endo.136.12.7588281 |
| Popis: | It is well established that uterine oxytocin receptors (OTRs) are strongly up-regulated immediately before parturition as well as in response to estrogen (E2) administration. Progesterone (P4), on the other hand, induces a rapid down-regulation. We recently cloned the rat OTR gene and characterized its expression in the rat uterus. In this study, we examined the regulation of OTR messenger RNA (mRNA) levels in rat uterus during pregnancy, the estrous cycle, and in response to gonadal steroid treatment. OTR mRNA levels increased more than 25-fold during gestation: 4.5-fold during the first 21 days and 6-fold within 24 h between day 21 and the onset of parturition. Uterine OTR mRNA levels fell rapidly by 85% within 24 h following parturition. By in situ hybridization, OTR mRNA was localized specifically to the longitudinal and circular layers of the myometrium but was not detected in the endometrium. During the estrous cycle, OTR mRNA levels increased 2-fold between metestrus and proestrus, whereas oxytocin (OT) binding rose more than 10-fold within this same interval. Treatment of ovariectomized rats with E2 lead to a significant increase in both OTR mRNA levels (4.4-fold) and OT binding (6-fold). Cotreatment with P4 strongly reduced OT binding by 75% (P0.01) but did not significantly affect the E2-induced rise in OTR mRNA (11% decrease, P0.1). Our data suggest that the increased expression of OT binding sites observed at the onset of labor and at proestrus is mediated, at least in part, by an E2-induced up-regulation of OTR gene expression. However, it also appears that OTR mRNA levels are not the sole determinants of uterine OT binding. Specifically, P4-mediated OTR down-regulation cannot be explained by an effect on OTR mRNA accumulation and may involve novel mechanisms acting at translational or posttranslational levels. |
| Databáze: | OpenAIRE |
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