摘要
采用放射免疫法测定了斜带石斑鱼卵、胚胎及仔鱼组织的三碘甲腺原氨酸 (T3)水平。斜带石斑鱼未受精卵中含有较高的T3水平 ,达每克体质量 2 75ng,于开口期升至每克体质量 6 2 8ng ,之后保持在较低水平。用T3浸泡处理 4～ 5周仔鱼 ,当T3浓度达到 10 - 8mol L以上时 ,外源T3才能引起组织T3水平增加 ;10 - 8mol L的作用比 10 - 7mol L的作用弱 ,浸泡 2 4h所引起的T3增加幅度明显高于 72h ;对 4周仔鱼的影响明显强于 5周仔鱼。这些结果证实了斜带石斑鱼卵中存在母源T3,其自身内分泌腺的分化可能始于孵化期或开口期 ,处于变态后期的仔鱼已具有一定的调节组织甲状腺素水平的能力。外源T3能影响 4～ 5周仔鱼组织T3水平的最低浓度为10 - 8mol L ,浸泡 2 4h对发育早期的仔鱼作用较强。用RT_PCR检测了斜带石斑鱼卵、胚胎及仔鱼生长激素(growthhormone,GH)mRNA的表达情况 ,表明未受精卵中有较高水平的GHmRNA表达 ,受精卵至囊胚期胚胎的GHmRNA表达水平较低 ,原肠期以后 ,胚胎GHmRNA的表达量明显增加 ,进一步证明硬骨鱼从受精卵开始就存在GHmRNA的表达 ,并在自身内分泌腺分化之前参与鱼类早期发育的调节。总之 ,斜带石斑鱼的早期发育受甲状腺素和生长激素的共同调节。
The tissue triiodothyronine(T_3) content and the expression of growth hormone gene during early development of grouper (Epinephelus coioides) were determined by radioimmunoassay (RIA) and reverse transcriptase_polymerase chain reaction (RT_PCR) respectively. T_3 content in unfertilized eggs was 2 75 ng/g BW (body weight). At the first feeding stage, the content of T_3 reached to 6 28 ng/g BW and then dropped to a low level until 55_days after hatched. The tissue T_3 level of 4_ and 5_week_old larvae could be obviously elevated when they were immersed in 0 01×10 -6 or 0 1×10 -6 T_3 in a dose_dependent manner. The treatment in 24 h was more effective than 72 h. These results showed that maternal T_3 supplement existed in grouper eggs and new_hatched larvae. The thyroid follicles of larvae might secret thyroxine at the first feeding stage. The external T_3 could enhance larvae tissue T_3 content by immersing larvae in 0 01×10 -6 or 0 1×10 -6 T_3. The 24 hrs treatment was more effective. Total RNA was extracted from pooled eggs or larvae at different development stages. Using a pair of special primers, the 560 bp DNA bands of growth hormone were amplified from the total RNA of eggs, embryos and larvae samples by RT_PCR. The growth hormone gene expression was high in unfertilized eggs, but decreased from fertilized eggs to blastula(fertilized 5 5 h), and increased from gastrula(fertilized 10 5 h)to day 14 after hatched. The results indicated that growth hormone mRNA expressed in grouper eggs, embryos and larvae. Growth hormone might be an important role in the development of grouper embryo and larvae. In conclusion, both of thyroid hormone and growth hormone contributed to the early development of grouper.
出处
《中山大学学报（自然科学版）》
CAS
CSCD
北大核心
2003年第4期74-78,共5页
Acta Scientiarum Naturalium Universitatis Sunyatseni
基金
国家 8 6 3资源与环境技术领域海洋生物技术主题资助项目 (2 0 0 1AA6 2 10 10 )
国家自然科学基金委农业倾斜专项基金项目 (39970 5 86 )
关键词
斜带石斑鱼
甲状腺素
生长激素
早期个体发育
thyroid hormone
growth hormone
early development
Epinephelus coioides
