长短日照下绍鸭性成熟时间,下丘脑GnRH-I、POMC和NPY mRNA表达的差异  

Difference in Sexual Maturation Ages and Levels of Hypothalamic GnRH-I , POMC and NPY mRNA in Shaoxing Ducks During Long- or Short-day Photoperiods

作　　者：倪迎冬[1] 周玉传[1] 王亚菊[1] 卢立志[1] 陈杰[1] 赵茹茜[1] 

机构地区：[1]南京农业大学动物生理生化重点开放实验室,江苏南京210095

出　　处：《Zoological Research》2005年第5期539-544,共6页动物学研究（英文）

基　　金：国家自然科学基金农业倾斜项目(39770540)

摘　　要：利用长日照和短日照环境调控绍鸭的性成熟时间,并采用反转录多聚酶链式反应(RT-PCR)方法, 检测两种日照组(n=6)鸭性成熟过程中下丘脑促性腺激素释放激素-Ⅰ(GnRH-Ⅰ)、阿片促黑激素皮质素 原(POMC)和神经肽Y(NPY)mRNA表达的发育性变化及日龄间差异。结果表明,长日照组性成熟时间较短 日照组提前30d。RT-PCR结果显示,两组鸭下丘脑GnRH-Ⅰ mRNA的发育性表达模式相似,从出雏至性成熟 过程中,其表达水平呈逐渐增加趋势;长日照组下丘脑GnRH-Ⅰ mRNA表达丰度均高于同日龄短日照组,并于 120日龄时其差异达显著水平。两组POMC mRNA的表达丰度呈现先增加后降低趋势,于性成熟前后显著下降; 日照长度对其基因表达具有显著影响。两组NPY mRNA表达水平分别于60和90日龄时显著升高,于性成熟时 显著下降,但光照对其基因表达无显著影响。下丘脑GnRH-Ⅰ基因表达的显著上调可能是禽类性成熟启动的关 键因素,也是长日照条件下绍鸭性早熟的主要原因;GnRH-Ⅰ表达的上调与下丘脑POMC和NPY mRNA表达变 化有关。Shaoxing ducks raised in long-day （LD） or short-day photoperiods （SD） matured at different ages. The aim of this study was to investigate the central mechanisms behind this difference. The results were as follows： Ducks raised in LD grew faster and matured earlier than those raised in SD. LD and SD ducks attained puberty at 120 and 150 days of age, respectively. Additionally, the hypothalamic gonadotropin-releasing hormone-Ⅰ （GnRH- Ⅰ ） pro-opiomelanocortin （POMC） and neuropeptide Y （NPY） mRNA abundance were detected by semi-quantitative RT-PCR using βactin or 18S rRNA as an internal standard. The results showed that, even though the profile of GnRH-Ⅰ mRNA expression was similar between two groups, which increased progressively during sexual maturation, the level was higher in LD ducks than in SD ducks of corresponding ages, especially at 120 days of age （P 〈 0.05 ）. The levels of hypothalamic POMC and NPY gene expression showed different patterns compared with GnRH- ~ gene. POMC and NPY mRNA reached the highest level on D60 or D90, then decreased significantly till D150. Multi-factor ANOVA analysis showed that the LD photoperiod stimulated the expression of hypothalamic GnRH-Ⅰ and POMC mRNA, but had no effect on NPY gene expression. These results suggest that the hypothalamic GnRH- Ⅰ gene is the key factor for the onset of puberty and earlier maturation for ducks raised in the LD photoperiod. Additionally, right before or at the onset of laying, the coincidence of down-regulation of POMC and NPY mRNA and up-regulation in GnRH-Ⅰ gene expression in hypothalamus indicates that GnRH-Ⅰ , POMC and NPY gene work synergistically underlying the onset of puberty in Shaoxing ducks.

关 键 词：促性腺激素释放激素-Ⅰ 阿片促黑激素皮质素原 神经肽Y 性成熟 光照 反转录多聚酶链式反应 绍鸭 

分 类 号：S834.89[农业科学—畜牧学]