Thyroid cold acclimation influences on norepinephrine metabolism in brown fat.
Thyroid cold acclimation influences on norepinephrine metabolism in brown fat.
复制标题
甲状腺冷适应对棕色脂肪中去甲肾上腺素代谢的影响。
DOI：
10.1152/ajpendo.1977.232.6.e565
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
M. Hamolsky
中科院分区：
文献类型：
--
作者：
D. R. Kennedy;R. P. Hammond;M. Hamolsky
去甲肾上腺素周转率和酪氨酸羟化酶活性测定在肩胛间棕色脂肪垫的大鼠在冷驯化，甲状腺功能亢进症，甲状腺切除术后。通过将大鼠放置在冷室中使其冷适应，一只大鼠一笼，持续6周。通过每天皮下注射L-甲状腺素（1 mg/kg），连续6天诱导甲状腺素亢进症。去甲肾上腺素周转率和酶活性测定在每个实验期结束时和甲状腺切除术后8周。去甲肾上腺素周转率在冷习服和甲状腺功能亢进期间增加，在甲状腺切除术后降低。冷驯化导致酪氨酸羟化酶活性的显着增加，而没有显着的影响，观察到在甲状腺功能亢进症或甲状腺切除术后的酶活性。没有条件产生的变化相比，在酪氨酸羟化酶的L-酪氨酸的表观Km的控制。冷驯化导致蝶呤辅因子酪氨酸羟化酶的表观Km值显著降低，而甲状腺素治疗和甲状腺切除术没有影响。
Norepinephrine turnover rates and tyrosine hydroxylase activities were determined in the interscapular brown fat pad of the rat during cold acclimation, hyperthyroxinism, and after thyroidectomy. Rats were cold acclimated by placement in a cold room, one rat to a cage, for a period of 6 wk. Hyperthyroxinism was induced by daily subcutaneous injections of L-thyroxine (1 mg/kg) for 6 days. Norepinephrine turnover rate and enzyme activity were determined at the end of each experimental period and at 8 wk after thyroidectomy. The rate of norepinephrine turnover increased during cold acclimation and hyperthyroxinism and decreased after thyroidectomy. Cold acclimation resulted in a significant increase in tyrosine hydroxylase activity, whereas no significant effect on enzyme activity was observed in hyperthyroxinism or after thyroidectomy. None of the conditions produced a change compared to controls in the apparent Km of tyrosine hydroxylase for L-tyrosine. Cold acclimation resulted in a significant decrease in the apparent Km of tyrosine hydroxylase for pterin cofactor, whereas thyroxine treatment and thyroidectomy had no effect.