Jennes L, Brame B, Centers A, Janovick J A, Conn P M
Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, Lexington 40536, USA.
Brain Res Mol Brain Res. 1995 Oct;33(1):104-10. doi: 10.1016/0169-328x(95)00113-7.
The purpose of the present study was to determine if gonadal steroids can alter the amounts of GnRH receptor mRNA in the pyramidal and granule neurons of the hippocampus of female and male rats and if GnRH causes a change in the production of inositol phosphates in hippocampal slices in vitro. The results show that in the ovariectomized rat the amount of GnRH receptor mRNA is increased to 137% in area CA1 and to 147% in area CA3 and in the dentate gyrus when compared to the ovariectomized, estradiol-progesterone treated animal. Similarly, in the orchidectomized male rat the amount of GnRH receptor mRNA is increased to 155% in area CA1, to 146% in area CA3 and to 145% in the dentate gyrus when compared to the intact male rat. There was no significant difference in the relative amounts of GnRH receptor mRNA when gonadectomized male and female rats were compared. Addition of GnRH (100 pM-1 microM) to hippocampal slices in vitro caused a dose-dependent increase in the production of [3H]inositol phosphate which was abolished by co-administration of a GnRH antagonist. The increase in inositol phosphate production was significantly higher at low doses of GnRH (100 pM-1 nM) in estradiol-progesterone treated female and in intact male rats when compared to gonadectomized rats. The results suggest that the amount of GnRH receptor mRNA in the hippocampus is at least in part regulated by gonadal steroids and that the steroid hormones can sensitize the GnRH target neurons to respond more robustly to a GnRH stimulus.
本研究的目的是确定性腺类固醇是否能改变雌性和雄性大鼠海马锥体神经元和颗粒神经元中促性腺激素释放激素（GnRH）受体mRNA的含量，以及GnRH是否会导致体外海马切片中肌醇磷酸生成的变化。结果显示，与切除卵巢并经雌二醇 - 孕酮处理的动物相比，去卵巢大鼠海马CA1区GnRH受体mRNA的含量增加到137%，CA3区增加到147%，齿状回增加到147%。同样，与完整雄性大鼠相比，去势雄性大鼠海马CA1区GnRH受体mRNA的含量增加到155%，CA3区增加到146%，齿状回增加到145%。比较去势的雄性和雌性大鼠时，GnRH受体mRNA的相对含量没有显著差异。在体外海马切片中添加GnRH（100 pM - 1 microM）会导致[3H]肌醇磷酸生成呈剂量依赖性增加，而同时给予GnRH拮抗剂可消除这种增加。与去势大鼠相比，在雌二醇 - 孕酮处理的雌性和完整雄性大鼠中，低剂量GnRH（100 pM - 1 nM）时肌醇磷酸生成的增加更为显著。结果表明，海马中GnRH受体mRNA的含量至少部分受性腺类固醇调节，并且类固醇激素可使GnRH靶神经元对GnRH刺激的反应更强烈。
