Yoshioka K, Yoshida T, Wakabayashi Y, Nishioka H, Kondo M
First Department of Internal Medicine and Biochemistry, Kyoto Prefectural University of Medicine, Japan.
Endocrinol Jpn. 1989 Aug;36(4):491-9. doi: 10.1507/endocrj1954.36.491.
The role of insulin in norepinephrine turnover (NE) and thermogenesis in brown adipose tissue (BAT) after acute cold-exposure was studied using streptozocin (STZ)-induced diabetic rats. NE turnover was estimated by the NE synthesis inhibition technique with alpha-methyl-p-tyrosine. BAT thermogenesis was estimated by measuring mitochondrial guanosine-5'-diphosphate (GDP), cytochrome oxidase activity and mitochondrial oxygen consumption in BAT at an ambient temperature of 22 degrees C and during a six-hour cold-exposure at 4 degrees C. In insulin-deficient diabetic rats, the NE turnover, mitochondrial GDP binding, cytochrome oxidase activity and mitochondrial oxygen consumption in BAT at 22 degrees C were significantly reduced, compared with those of control rats. Treatment of STZ-induced diabetic rats with insulin prevented a decrease in NE turnover and BAT thermogenesis. Acute cold-exposure increased the NE turnover of BAT in insulin-deficient diabetic rats. The BAT thermogenic response to acute cold-exposure, however, did not occur in insulin-deficient diabetic rats. These results suggest that insulin is not essential in potentiating NE turnover in BAT after acute cold-exposure, but is required for cold-induced thermogenesis.
利用链脲佐菌素（STZ）诱导的糖尿病大鼠，研究了急性冷暴露后胰岛素在棕色脂肪组织（BAT）中去甲肾上腺素周转（NE）和产热中的作用。通过用α-甲基-p-酪氨酸的NE合成抑制技术来估计NE周转。通过在22℃环境温度下以及在4℃进行6小时冷暴露期间测量BAT中的线粒体鸟苷-5'-二磷酸（GDP）、细胞色素氧化酶活性和线粒体氧消耗来估计BAT产热。与对照大鼠相比，胰岛素缺乏的糖尿病大鼠在22℃时BAT中的NE周转、线粒体GDP结合、细胞色素氧化酶活性和线粒体氧消耗显著降低。用胰岛素治疗STZ诱导的糖尿病大鼠可防止NE周转和BAT产热的降低。急性冷暴露增加了胰岛素缺乏的糖尿病大鼠BAT中的NE周转。然而，胰岛素缺乏的糖尿病大鼠对急性冷暴露没有发生BAT产热反应。这些结果表明，胰岛素在急性冷暴露后增强BAT中NE周转方面不是必需的，但冷诱导的产热需要胰岛素。
