Laboratorio de Fisiopatología Ovárica, Instituto de Medicina y Biología Experimental de Cuyo (IMBECU - CONICET Mendoza), Mendoza, Argentina.
Facultad de Ingeniería y Facultad de Ciencias Médicas, Universidad de Mendoza, Mendoza, Argentina.
J Neuroendocrinol. 2020 Mar;32(3):e12836. doi: 10.1111/jne.12836. Epub 2020 Feb 16.
The present study aimed to determine whether an i.c.v. administration of allopregnanolone (ALLO) rapidly modifies the hypothalamic and ovarian 3β-hydroxysteroid dehydrogenase (3β-HSD) enzymatic activity and gene expression in in vivo and ex vivo systems in pro-oestrus (PE) and dioestrus I (DI) rats. Animals were injected with vehicle, ALLO, bicuculline or bicuculline plus ALLO and were then killed. In the in vivo experiment, the hypothalamus, ovaries and serum were extracted and analysed. In the ex vivo experiment, the superior mesenteric ganglion - ovarian nerve plexus - ovary system was extracted and incubated during 120 minutes at 37 ºC. The serum and ovarian compartment fluids were used to determine progesterone by radioimmunoanalysis. In the in vivo experiments, ALLO caused a decrease in hypothalamic and ovarian 3β-HSD enzymatic activity during PE. During DI, ALLO increased hypothalamic and ovarian 3β-HSD activity and gene expression. The ovarian 3β-HSD activity increased in both stages in the ex vivo system; gene expression increased only during DI. ALLO induced an increase in serum progesterone only in D1 and in the ovarian incubation liquids in both stages. All findings were reversed by an injection of bicuculline before ALLO. Ovarian steroidogenic changes could be attributed to signals coming from ganglion neurones, which are affected by the acute central neurosteroid stimulation. The i.c.v. administration of ALLO via the GABAergic system altered 3β-HSD activity and gene expression, modulating the neuroendocrine axis. The present study reveals the action that ALLO exerts on the GABAA receptor in both the central and peripheral nervous system and its relationship with hormonal variations. ALLO is involved in the "fine tuning" of neurosecretory functions as a potent modulator of reproductive processes in female rats.
本研究旨在确定在体内和体外系统中，侧脑室给予别孕烯醇酮（ALLO）是否能迅速改变动情前期（PE）和动情间期 I（DI）大鼠下丘脑和卵巢 3β-羟甾脱氢酶（3β-HSD）的酶活性和基因表达。动物被注射载体、ALLO、印防己毒素或印防己毒素加 ALLO 后被处死。在体内实验中，提取下丘脑、卵巢和血清并进行分析。在体外实验中，提取肠系膜上神经节-卵巢神经丛-卵巢系统并在 37°C 下孵育 120 分钟。使用放射免疫分析法测定血清和卵巢腔液中的孕酮。在体内实验中，ALLO 在 PE 期间导致下丘脑和卵巢 3β-HSD 酶活性降低。在 DI 期间，ALLO 增加了下丘脑和卵巢 3β-HSD 活性和基因表达。在体外系统中，卵巢 3β-HSD 活性在两个阶段都增加；基因表达仅在 DI 期间增加。ALLO 仅在 DI 期间诱导血清孕酮和卵巢孵育液中孕酮增加。在 ALLO 之前注射印防己毒素可逆转所有发现。卵巢甾体生成变化可归因于来自神经节神经元的信号，这些信号受急性中枢神经甾体刺激的影响。通过 GABA 能系统向侧脑室给予 ALLO 可改变 3β-HSD 活性和基因表达，调节神经内分泌轴。本研究揭示了 ALLO 在中枢和外周神经系统中对 GABAA 受体的作用及其与激素变化的关系。ALLO 作为雌性大鼠生殖过程的有效调节剂，参与了神经分泌功能的“微调”。
