Müller C, Voirol M J, Stefanoni N, Surmely J F, Jéquier E, Gaillard R C, Tappy L
Institut de physiologie, Faculté de médecine, Université de Lausanne, Switzerland.
Int J Obes Relat Metab Disord. 1997 Jul;21(7):562-6. doi: 10.1038/sj.ijo.0800441.
Carbohydrate feeding stimulates, and fasting decreases the sympathetic nervous system activity and brown adipose tissue (BAT) thermogenesis. This study was performed to assess the hypothesis that these effects were secondary to changes in insulin concentrations in the central nervous system.
BAT sympathetic activity was assessed by comparing 3H-GDP binding to isolated mitochondria of innervated and denervated interscapular BAT of three groups of 10 week old male Wistar rats: food-restricted, 48 h fasted or ad libitum fed. During the three days preceding this measurement, animals received a continuous intracerebroventricular (ivc) infusion of insulin (0.48 U/d) or vehicle.
In food-restricted rats, 3H-GDP binding to mitochondria of innervated BAT was 41% higher than that to denervated BAT. Icv insulin did not stimulate 3H-GDP binding in innervated BAT. In 48 h fasted rats, 3H-GDP binding to mitochondria of innervated BAT was reduced by 30-50%, while the activity of denervated BAT was minimally affected. Icv insulin did not prevent this fasting-induced drop in BAT. In rats fed ad libitum, icv insulin decreased food intake by 17% (P < 0.05) and increased 3H-GDP binding to innervated BAT by 27% (P < 0.05).
Intracerebroventricular insulin stimulates BAT activity in rats fed ad libitum but not in food-restricted or fasted rats. This demonstrates that the decrease in BAT activity observed during fasting is unlikely to be due to a decrease in insulin concentration in the nervous system.
碳水化合物喂养可刺激交感神经系统活动，而禁食则会降低该活动以及棕色脂肪组织（BAT）的产热。本研究旨在评估以下假设，即这些效应是中枢神经系统中胰岛素浓度变化的继发结果。
通过比较三组10周龄雄性Wistar大鼠（食物限制组、禁食48小时组或自由进食组）的去神经和未去神经肩胛间BAT分离线粒体上的³H - GDP结合情况，来评估BAT交感神经活动。在进行该测量的前三天，动物接受胰岛素（0.48 U/天）或载体的持续脑室内（icv）输注。
在食物限制的大鼠中，³H - GDP与未去神经BAT线粒体的结合比去神经BAT高41%。脑室内注射胰岛素并未刺激未去神经BAT中的³H - GDP结合。在禁食48小时的大鼠中，³H - GDP与未去神经BAT线粒体的结合减少了30 - 50%，而去神经BAT的活性受影响最小。脑室内注射胰岛素未能阻止禁食引起的BAT下降。在自由进食的大鼠中，脑室内注射胰岛素使食物摄入量减少了17%（P < 0.05），并使³H - GDP与未去神经BAT的结合增加了27%（P < 0.05）。
脑室内注射胰岛素可刺激自由进食大鼠的BAT活性，但对食物限制或禁食大鼠无效。这表明禁食期间观察到的BAT活性下降不太可能是由于神经系统中胰岛素浓度降低所致。
