性类固醇激素E_2、MT对尼罗罗非鱼(Oreochromis niloticus)雌、雄生长差异的影响  

STEROID HORMONES(E_2 AND MT) DISPLAYED DIFFERENCE IN SEX FOR NILE TILAPIA OREOCHROMIS NILOTICUS

作　　者：马细兰[1] 张勇[2] 陈勇智[1] 周立斌[1] 

机构地区：[1]惠州学院生命科学系生物技术研究所,惠州516007 [2]中山大学生命科学学院水生经济动物研究所暨广东省水生经济动物良种繁育重点实验室,广州510275

出　　处：《海洋与湖沼》2015年第6期1487-1493,共7页Oceanologia Et Limnologia Sinica

基　　金：国家自然科学基金项目;31201978号;惠州学院自然科学重点项目;2012ZD07号

摘　　要：性类固醇激素对动物生长有一定的影响,但其对鱼类雌、雄生长差异的影响机理尚不清楚。为进一步了解动物雌雄生长差异的内在原因,本文通过在体注射和荧光定量PCR方法,比较了性类固醇激素(E_2、MT)对尼罗罗非鱼雌鱼和雄鱼的生长及对垂体GH、肝脏GHR1、IGF-I m RNA表达的影响。结果表明:性类固醇激素E2和MT对尼罗罗非鱼的生长及生长轴相关基因的表达均有显著的影响,并且这种影响存在明显的性别二态性。E_2明显促进雌鱼的生长但不显著影响雄鱼的生长,MT显著促进雄鱼和雌鱼的生长;E2可使雌鱼垂体GH和肝脏GHR1、IGF-I的m RNA水平显著升高(P<0.05),但降低雄鱼垂体GH和肝脏GHR1的m RNA表达;MT显著提高雄鱼垂体GH和肝脏GHR1、IGF-I m RNA水平(P<0.05),但降低雌鱼垂体GH的m RNA表达,促进雌鱼肝脏GHR1 m RNA的表达,但对雄鱼肝脏GHR1的促进作用明显大于雌鱼(P<0.05)。上述结果表明,性类固醇激素对不同性别尼罗罗非鱼的生长及生长轴相关基因的m RNA表达有不同的影响,表现出明显的性别二态性,提示不同性别鱼体内性类固醇激素水平的不同可能是导致尼罗罗非鱼雌雄生长二态性的另一内在原因。Steroid hormone affects the growth of fish sexual dimorphism, and the mechanism remains unclear. Nile tilapia（Oreochromis niloticus） is a fresh water fish with obvious sexual dimorphism. The effects of steroid hormone on the growth and expressions of GH in pituitary, GHR and IGF-I mRNA in liver of Nile tilapia were studied. Two experiments in a long and short period were designated and carried out. In the long-period experiment, 200 fish individuals in similar body size were randomly assigned into the control group [intraperitoneal injection（i. p.） with fish physiological saline, PS], the E2 group（i. p. with E2, 50μg/g body weight）, and the MT group（i. p. with MT, 50μg/g body weight）, and fed for 70 days under the same natural conditions. Result shows that E2 significantly promoted female growth and enhanced female GH, GHR1, and IGF-I mRNA expressions（P〈0.05）, but for males not in growth nor GH, GHR1 mRNA expressions. However, MT boosted significantly the growth of both sexes. MT improved GH for males, and GHR1 expressions for both sexes but greater in male than in female（P〈0.05）. Therefore, steroid hormones affected the growth and the genes expression in different ways in sex, which may become a reason for the dimorphism of the fish.

关 键 词：尼罗罗非鱼 E2 MT 雌雄生长差异 基因表达 

分 类 号：Q956[生物学—动物学]