甲状腺激素对白头鹎基础产热的影响

甲状腺激素对动物的基础产热有调节作用,甲状腺活性的增加往往与基础代谢的增加相伴行。通过每日饲喂甲状腺素(T4)研究了甲状腺机能亢进对白头鹎(Pycnonotus sinensis)代谢产热的影响。代谢率的测定采用封闭式流体压力呼吸计测定,细胞色素C氧化酶(COX)采用铂氧电极-溶氧仪测定,反应温度为30℃,肝脏和肌肉的线粒体状态4呼吸采用铂氧电极-溶氧仪测定,反应温度为30℃,线粒体蛋白的测定以牛血清蛋白作为标准,采用Folin-phenol方法,测定肝脏和肌肉组织的蛋白质含量。与对照组相比,甲亢组的基础代谢率(BMR)明显升高;肝脏及肌肉组织状态4呼吸增加;肝脏和肌肉线粒体的COX活力升高。

The effects of thyroid hormone on basal thermogenesis in (Pycnonotus sinensis)

Thyroid hormones (thyroxine T_4 and triiodothyronine T_3) are unique in their ability to stimulate basal thermogenesis for small birds.The present study aims to examine the effect of thyroid hormones on thermogenesis in hyperthyroid Chinese bulbuls (Pycnonotus sinensis) that was fed T_4 laced poultry food for 3 weeks.Birds were housed at room temperature (18-26℃) .The rate of oxygen consumption was measured using the closed-circuit respirometer.The mitochondrial protein contents were determined by the Folin phenol method with bovine serum albumin as a standard.Respiration of liver and muscle mitochondria were measured polarographically at 30℃ in the presence of succinate using an oxygen electrode units (Hansatech Instruments Ltd.,English) .The activity of cytochrome C oxidase (COX) was also determined polarographically at 30℃.Chinese bulbuls fed on 104-laced poultry food showed increases in basal metabolic rate (BMR) during 3-week acclimation.Finally,these bulbuls had higher levels of mitochondrial protein contents in muscle,state 4 respiration and COX activity in liver and muscle and serum T_4 and T_3 contents than that of control bulbuls.These results provide support for the hypothesis that thyroid hormones play an important role in the regulation of thermogenic ability by stimulating mitochondrial respiration and enzyme activities associated with aerobic metabolism.