Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Institut National de la Sante´ et de la Recherche Me´ dicale U982, Research Institute for Biomedecine (IRIB), International Associated Laboratory Samuel de Champlain, University of Rouen, 76821 Mont-Saint Aignan, France.
Endocrinology. 2013 Jun;154(6):2114-28. doi: 10.1210/en.2013-1095. Epub 2013 Apr 3.
The sulfated neurosteroids pregnenolone sulfate (Δ(5)PS) and dehydroepiandrosterone sulfate (DHEAS) are known to play a role in the control of reproductive behavior. In the frog Pelophylax ridibundus, the enzyme hydroxysteroid sulfotransferase (HST), responsible for the biosynthesis of Δ(5)PS and DHEAS, is expressed in the magnocellular nucleus and the anterior preoptic area, two hypothalamic regions that are richly innervated by GnRH1-containing fibers. This observation suggests that GnRH1 may regulate the formation of sulfated neurosteroids to control sexual activity. Double labeling of frog brain slices with HST and GnRH1 antibodies revealed that GnRH1-immunoreactive fibers are located in close vicinity of HST-positive neurons. The cDNAs encoding 3 GnRH receptors (designated riGnRHR-1, -2, and -3) were cloned from the frog brain. RT-PCR analyses revealed that riGnRHR-1 is strongly expressed in the hypothalamus and the pituitary whereas riGnRHR-2 and -3 are primarily expressed in the brain. In situ hybridization histochemistry indicated that GnRHR-1 and GnRHR-3 mRNAs are particularly abundant in preoptic area and magnocellular nucleus whereas the concentration of GnRHR-2 mRNA in these 2 nuclei is much lower. Pulse-chase experiments using tritiated Δ(5)P and DHEA as steroid precursors, and 3'-phosphoadenosine 5'-phosphosulfate as a sulfonate moiety donor, showed that GnRH1 stimulates, in a dose-dependent manner, the biosynthesis of Δ(5)PS and DHEAS in frog diencephalic explants. Because Δ(5)PS and DHEAS, like GnRH, stimulate sexual activity, our data strongly suggest that some of the behavioral effects of GnRH could be mediated via the modulation of sulfated neurosteroid production.
已知硫酸神经甾体孕烯醇酮硫酸盐 (Δ(5)PS) 和脱氢表雄酮硫酸盐 (DHEAS) 在控制生殖行为方面发挥作用。在青蛙 Pelophylax ridibundus 中，负责 Δ(5)PS 和 DHEAS 生物合成的羟甾类硫酸转移酶 (HST) 表达于大细胞核和前视前区，这两个下丘脑区域富含含有 GnRH1 的纤维。这一观察结果表明，GnRH1 可能通过调节硫酸神经甾体的形成来控制性行为。用 HST 和 GnRH1 抗体对青蛙脑切片进行双重标记显示，GnRH1 免疫反应性纤维位于 HST 阳性神经元的附近。从青蛙脑中克隆出编码 3 种 GnRH 受体 (命名为 riGnRHR-1、-2 和 -3) 的 cDNA。RT-PCR 分析显示 riGnRHR-1 在下丘脑和垂体中强烈表达，而 riGnRHR-2 和 -3 主要在脑中表达。原位杂交组织化学表明 GnRHR-1 和 GnRHR-3 mRNA 在视前区和大细胞核中特别丰富，而 GnRHR-2 mRNA 在这两个核中的浓度要低得多。使用氚标记的 Δ(5)P 和 DHEA 作为类固醇前体，以及 3'-磷酸腺苷 5'-磷酸硫酸作为硫酸酯部分供体进行的脉冲追踪实验表明，GnRH1 以剂量依赖性方式刺激青蛙间脑外植体中 Δ(5)PS 和 DHEAS 的生物合成。由于 Δ(5)PS 和 DHEAS 与 GnRH 一样刺激性行为，我们的数据强烈表明，GnRH 的一些行为效应可能通过调节硫酸神经甾体的产生来介导。
