【摘要】 本文通过测定静止代谢率(RMR)、非颤抖性产热(NST)、线粒体呼吸酶、脂肪代谢酶活力、褐色脂肪组织(BAT)线粒体GTP结合能力、下丘脑促甲状腺激素释放激素(TRH)和促肾上腺激素释放激素(CRH)等指标,探讨短光照对达乌尔黄鼠产热的诱导和调节。结果表明,温暖(22℃)短光照(8D∶6L)组,达乌尔黄鼠的RMR、NST、肝脏和BAT线粒体细胞色素C氧化酶活力以及BAT线粒体GTP结合能力均明显高于温暖长光照(16D∶8L)组中的动物,而体重、BAT重量、肝细胞呼吸、BATα-磷酸甘油氧化酶活力则没有明显变化。短光照组黄鼠下丘脑TRH水平显著高于长光照组,而血清中三碘甲腺原氨酸(T3)及甲状腺素(T4)浓度、T3/T4以及BAT中T4-5’脱碘酶的活性没有明显变化。短光照组黄鼠下丘脑CRH水平显著高于对照组,而肾上腺皮质酮含量无明显变化。结果表明短光照能够诱导达乌尔黄鼠产热增加,主要是通过激活细胞色素C氧化酶活性和增加BAT中解偶联蛋白浓度;短光照可能激活下丘脑TRH和CRH,但它们没有直接诱导产热增加,推测其增加了黄鼠潜在的产热能力。更多还原

【Abstract】 Thermogenesis and thermoregulation induced by short photoperiod were investigated in Daurian ground squirrels(Spermophilus dauricus)by measuring resting metabolic rate(RMR),nonshivering thermogenesis(NST),activity of cytochrome C oxidase(CCO)of liver and brown adipose tissues(BAT),BAT mitochondrial GTP-binding capacity,and hypothalamic thyrotropin-releasing hormone(TRH)and corticotrophin-releasing hormone(CRH)levels in squirrels.The results showed that the RMR,NST,CCO activity,and BAT mitochondrial GTP-binding capacity were markedly increased by exposure to short photoperiod(8D∶16L,SP)and constant ambient temperature(22±2℃)relative to those for long photoperiod(16D∶8L,22±2℃,LP),while body weight and BAT mass,hepatic mitochondrial respiration,and BAT α-glycerophosphate oxidase activity were not significantly changed.The short photoperiod induced higher hypothalamic TRH and CRH levels than did the LP.However,the serum concentration of triiodothyronine(T 3),thyroxine(T 4),the ratio of T 3 and T 4,the activity of T 4 5’-deiodinase in BAT,and the adrenal corticosterone level showed no significantly change.The results suggest that the short photoperiod may induce an increased thermogenesis in Daurian ground squirrel’s through activating CCO and enhancing uncoupling-protein levels in BAT,and simultaneously activating hypothalamic TRH and CRH that do not directly induce an increased hermogenesis but may be a potential factor.更多还原