鳙、团头鲂和短盖巨脂鲤早期发育阶段甲状腺激素含量变化研究

鳙、团头鲂和短盖巨脂鲤胚胎与仔鱼体内三碘甲腺原氨酸和四状腺素含量的变化，采用放射免疫测定法进行测定，研究发现胚胎阶段的Ｔ３和Ｔ４含较稳定，出膜后仔鱼阶段的Ｔ３和Ｔ４含量逐渐下降。

Changes of thyroid hormone content in big head carp, blunt snout bream and pacu during early developmental stages

Changes of the thyroid hormone content in the embryos and larvae of big head carp (Aristichthys nobilis), blunt snout bream (Megalobrama amblycephala) and pacu (Colossoma rachypomum) were measured by using radioimmunoassay. The levels of triodothyronine (T3) and thyroxin(T4) during the embryonic stages in blunt snout bream and big head carp were rather stable.The levels of T3 and T4 in the hatehed driae of the three species decreased gradually In combination with the studies of the development of typrical thyroid foilicle strutures in three species. It was found that the earliest appearance of the thyroid follicles were present around the ventral arota in the pharynxgill region, the time of typical thyroid foilicles appearance coincide with the T4 level rising in tha fish.The results indicated tha the changes of the thwid hormone level during early development were caused by the depletion of maternal origin thyroid hormon and the onset of thyroid gland function in lera.