Singh Padmasana, Krishna Amitabh, Sridaran Rajagopala, Tsutsui Kazuyoshi
Department of Zoology, Banaras Hindu University, Lanka, Varanasi 221005, India.
Gen Comp Endocrinol. 2008 Nov-Dec;159(2-3):158-69. doi: 10.1016/j.ygcen.2008.08.016. Epub 2008 Sep 10.
The aim of this study was to investigate changes in the abundance of gonadotrophin releasing hormone I (GnRH I) and GnRH I receptor in the ovary of Calotes versicolor during the reproductive cycle and correlate them with the changes in gonadotrophin inhibitory hormone (GnIH), bradykinin and bradykinin B(2) receptor in order to understand their interaction during ovarian cycle. GnRH I, bradykinin and their receptors and GnIH, were localized immunohistochemically in the ovary. Relative intensity of these peptides was estimated from the contralateral ovary using slot/Western blot followed by densitometry. The immunostaining of GnRH I, bradykinin and their receptors and GnIH were localized in the granulosa cells of previtellogenic follicles and stroma cells, whereas in the peripheral part of the cytoplasm in oocytes of vitellogenic and ovulatory follicles. The GnRH I immunostaining was relatively higher in inactive phase, but was low during active preovulatory phase suggesting inverse correlation with circulating estradiol level. The study showed a positive correlation between the expression pattern of GnRH I and GnIH, but showed a negative correlation between GnIH with GnRH I receptor in the ovary. This study further suggests a possibility for bradykinin regulating GnRH I synthesis in the ovary. An increase in the immunostaining of both GnRH I and GnIH in the oocyte prior to ovulation suggests their involvement in the oocyte maturation. It is thus concluded that the ovary of C. versicolor possesses GnRH I-GnIH-bradykinin system and interaction between these neuropeptides may be involved in the regulation of follicular development and oocyte maturation.
本研究的目的是调查变色树蜥卵巢在生殖周期中促性腺激素释放激素I（GnRH I）和GnRH I受体丰度的变化，并将它们与促性腺激素抑制激素（GnIH）、缓激肽和缓激肽B2受体的变化相关联，以了解它们在卵巢周期中的相互作用。GnRH I、缓激肽及其受体以及GnIH通过免疫组织化学定位在卵巢中。使用狭缝/蛋白质免疫印迹法随后进行光密度测定，从对侧卵巢估计这些肽的相对强度。GnRH I、缓激肽及其受体以及GnIH的免疫染色定位于卵黄生成前卵泡的颗粒细胞和基质细胞，而在卵黄生成和排卵卵泡的卵母细胞细胞质周边部分。GnRH I免疫染色在静止期相对较高，但在排卵前活跃期较低，表明与循环雌二醇水平呈负相关。该研究表明GnRH I和GnIH的表达模式之间呈正相关，但在卵巢中GnIH与GnRH I受体之间呈负相关。本研究进一步提示缓激肽可能调节卵巢中GnRH I的合成。排卵前卵母细胞中GnRH I和GnIH的免疫染色增加表明它们参与卵母细胞成熟。因此得出结论，变色树蜥的卵巢拥有GnRH I - GnIH - 缓激肽系统，这些神经肽之间的相互作用可能参与卵泡发育和卵母细胞成熟的调节。
