Dave Anushree, Krishna Amitabh, Tsutsui Kazuyoshi
Department of Zoology, Institute of Sciences, Banaras Hindu University, Varanasi 221 005, India.
Department of Zoology, Institute of Sciences, Banaras Hindu University, Varanasi 221 005, India.
Gen Comp Endocrinol. 2017 Oct 1;252:193-199. doi: 10.1016/j.ygcen.2017.06.024. Epub 2017 Jun 26.
Arg(R)-Phe(F)-amide related peptide-1 (RFRP-1) and -3 (RFRP-3) are known as mammalian orthologs of gonadotropin-inhibitory hormone (GnIH). In mammals, these RFRPs are expressed not only in the hypothalamus and but also in gonads. Inhibitory roles of the hypothalamic and gonadal RFRP-3 in reproduction have been documented in mammals. However, functional roles of the hypothalamic and gonadal RFRP-1 in reproduction are still unclear in mammals. Therefore, in vitro studies were conducted to elucidate the direct effect of RFRP-1, a mammalian GnIH ortholog, on ovarian activities, such as steroidogenesis, apoptosis, cell proliferation and metabolism in the cyclic mouse. The ovaries collected from the proestrus mice were cultured in vitro with different doses (Control, 1ng/ml, 10ng/ml and 100ng/ml) of RFRP-1 for 24h at 37°C. A significant dose-dependent increase in estradiol release from the ovary was detected after the treatment of RFRP-1. Therefore, changes in the ovarian activities, such as steroidogenic markers (luteinizing hormone receptors; LH-R and 3β-hydroxysteroid dehydrogenase; 3β-HSD), apoptotic markers [Poly(ADP-ribose) polymerase-1; PARP-1 and cysteine-aspartic protease; caspase-3], a cell proliferation marker (proliferating cell nuclear antigen; PCNA) and metabolic markers (GLUT-4; glucose uptake) were assessed by the treatment of RFRP-1 in the proestrus ovary. The densitometry analysis showed the treatment of RFRP-1 significantly increased the expressions of LH-R and 3β-HSD, steroidogenic markers. In contrast, the expressions of PCNA, a cell proliferation maker; PARP-1 and caspase-3, apoptotic markers were significantly decreased. Interestingly, RFRP-1 treatment further increases significantly glucose uptake and GLUT-4 receptor expression. These findings indicate that RFRP-1 possesses a stimulatory effect on ovarian steroidogenesis in the proestrus mouse. This is the first evidence showing the direct action of RFRP-1 on steroidogenesis in any vertebrate. In addition, RFRP-1 may also act directly on ovarian folliculogenesis as an inhibitory factor.
精氨酸（R）-苯丙氨酸（F）-酰胺相关肽-1（RFRP-1）和-3（RFRP-3）被认为是促性腺激素抑制激素（GnIH）的哺乳动物直系同源物。在哺乳动物中，这些RFRP不仅在下丘脑表达，也在性腺中表达。下丘脑和性腺RFRP-3在繁殖中的抑制作用已在哺乳动物中得到证实。然而，下丘脑和性腺RFRP-1在繁殖中的功能作用在哺乳动物中仍不清楚。因此，进行了体外研究，以阐明哺乳动物GnIH直系同源物RFRP-1对周期性小鼠卵巢活动的直接影响，如类固醇生成、细胞凋亡、细胞增殖和代谢。从发情前期小鼠收集的卵巢在37℃下用不同剂量（对照、1ng/ml、10ng/ml和100ng/ml）的RFRP-1体外培养24小时。用RFRP-1处理后，检测到卵巢中雌二醇释放量呈显著的剂量依赖性增加。因此，通过在发情前期卵巢中用RFRP-1处理，评估了卵巢活动的变化，如类固醇生成标志物（促黄体生成素受体；LH-R和3β-羟基类固醇脱氢酶；3β-HSD）、凋亡标志物[聚（ADP-核糖）聚合酶-1；PARP-1和半胱天冬酶；caspase-3]、细胞增殖标志物（增殖细胞核抗原；PCNA）和代谢标志物（葡萄糖转运蛋白4；GLUT-4；葡萄糖摄取）。光密度分析表明，用RFRP-1处理显著增加了类固醇生成标志物LH-R和3β-HSD的表达。相反，细胞增殖标志物PCNA、凋亡标志物PARP-1和caspase-3的表达显著降低。有趣的是，RFRP-1处理进一步显著增加了葡萄糖摄取和GLUT-4受体表达。这些发现表明，RFRP-1对发情前期小鼠的卵巢类固醇生成具有刺激作用。这是首次证明RFRP-1在任何脊椎动物中对类固醇生成具有直接作用的证据。此外，RFRP-1也可能作为一种抑制因子直接作用于卵巢卵泡发生。
