Bale T L, Pedersen C A, Dorsa D M
Department of Pharmacology, University of Washington, Seattle 98195, USA.
Adv Exp Med Biol. 1995;395:269-80.
A genomic clone was used to generate a rat oxytocin receptor (OTR) probe for in situ hybridization studies in order to monitor changes in expression of OTR mRNA in the CNS of male and female rats in brain regions reported to be rich in OTR binding. This probe predominantly detects expression in the ventromedial hypothalamus (VMH). Quantitatively greater expression of OTR mRNA was more evident in the male VMH than in that of the female. OTR mRNA expression in the VMH is also enhanced in gonadectomized rats treated with either estrogen or testosterone. Previous studies of VMH OTR mRNA expression during the estrous cycle revealed a role of estrogen in proestrous OTR mRNA expression and also provided evidence for progesterone's modulatory effect on OTR expression. A related study which examined OTR mRNA expression during gestation, parturition, and lactation further supported the regulation of the OTR by gonadal steroids, as a pronounced induction of expression occurred at parturition when estrogen levels were highest. These results support previous studies which have documented the regulation of OTR binding by gonadal steroids and suggest that this regulation may be the result of altered expression of the OTR gene. Induction of OTRs in anatomically distinct regions of the VMH may be important in promoting OT'ergic neurotransmission required for sexual behavior or the induction of gonadotropin release by OT, which requires estrogen and progesterone priming. The anatomical variation in OTR mRNA localization and its restricted detection in the VMH by this probe suggests potential CNS OTR heterogeneity.
为了监测雄性和雌性大鼠中枢神经系统（CNS）中富含催产素受体（OTR）结合的脑区中OTR mRNA表达的变化，使用基因组克隆生成大鼠OTR探针用于原位杂交研究。该探针主要检测腹内侧下丘脑（VMH）中的表达。雄性VMH中OTR mRNA的表达在数量上比雌性更明显。用雌激素或睾酮处理的去性腺大鼠中，VMH中OTR mRNA的表达也会增强。先前关于发情周期中VMH OTR mRNA表达的研究揭示了雌激素在发情前期OTR mRNA表达中的作用，也为孕酮对OTR表达的调节作用提供了证据。一项相关研究检查了妊娠、分娩和哺乳期的OTR mRNA表达，进一步支持了性腺类固醇对OTR的调节作用，因为在雌激素水平最高的分娩时出现了明显的表达诱导。这些结果支持了先前记录性腺类固醇对OTR结合调节的研究，并表明这种调节可能是OTR基因表达改变的结果。VMH不同解剖区域中OTR的诱导对于促进性行为所需的OT能神经传递或OT诱导促性腺激素释放可能很重要，而这需要雌激素和孕酮的启动。OTR mRNA定位的解剖学差异及其通过该探针在VMH中的有限检测表明中枢神经系统中可能存在OTR异质性。
