Central and peripheral nervous system regulation of fat metabolism.

1. 研究了下丘脑腹内侧（VMH）刺激对大鼠棕色脂肪组织（BAT）脂质代谢和产热的影响。发现VMH电刺激优先引起BAT中甘油三酯合成速率的显著增加，并使该组织的温度迅速升高。由于已经知道刺激VMH可以诱导脂肪组织中甘油三酯的分解，这些结果表明，VMH刺激通过加速甘油三酯的分解和再合成（即转化）来增加BAT中的产热作用。BAT对VMH刺激的产热和产脂反应几乎完全被手术切除BAT的交感神经支配所消除，这表明VMH刺激的作用是由该组织的交感神经供应介导的。研究了双侧VMH病变对大鼠BAT代谢的影响，以及与下丘脑病变后肥胖发展的关系。VMH更多的溶解性病变导致甘油三酯的积累和BAT的肥大，这与组成脂肪细胞的增大以及它们从多室脂滴结构明显转变为单室结构有关。VMH病变后，BAT脂肪酸合成速率和交感神经刺激下BAT温度升高均明显降低。这些结果表明，在VMH病变大鼠中，BAT的产热作用通过降低组织中甘油三酯的转换而受到损害，这可能有助于VMH病变引起的肥胖的发展。研究了迷走神经切断术和交感神经切断术对大鼠肝脏中胆固醇合成限速酶HMG-CoA还原酶活性日波动的影响。双侧膈下迷走神经切断术抑制了酶活性的正常日波动，而肝交感神经切断术则倾向于放大酶活性的日波动。结果表明，肝脏胆固醇生成活性的日波动受神经的影响。少

1. Effects of ventromedial hypothalamic (VMH) stimulation on lipid metabolism and thermogenesis in brown adipose tissue (BAT) were studied in rats. Electrical stimulation of VMH was found to cause a marked increase in the rate of triglyceride synthesis in BAT preferentially and a rapid rise in the temperature of this tissue. Since stimulation of VMH has already been known to induce breakdown of triglycerides in adipose tissues, these results suggest that VMH stimulation increases thermogenesis in BAT by accelerating both the breakdown and resynthesis, that is, the turnover, of triglycerides. The thermogenic and lipogenic responses of BAT to VMH stimulation were almost completely abolished by surgical sympathetic denervation of BAT, indicating that the effects of VMH stimulation are mediated by the sympathetic nerve supply of this tissue.2. Effects of bilateral lesions of VMH on BAT metabolism were studied in rats, in relation to a development of obesity after hypothalamic lesions. Elec … More trolytic lesions of VMH led to accumulation of triglycerides and hypertrophy of BAT, which were associated with enlargement of constituent adipocytes and their apparent transformation from multiloculated structure of lipid droplets into the uniloculated structure. The rate of fatty acid synthesis in BAT and its temperature rise in response to sympathetic nerve stimulation were both reduced markedly after VMH lesions. These results indicated that thermogenesis in BAT was impaired in rats with VMH lesions by decreasing triglyceride turnover in the tissue, which might contribute to the development of obesity induced by VMH lesions.3. Effects of surgical vagotomy and sympathectomy on diurnal fluctuation of the activity of HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis, were studied in rat liver. Bilateral subdiaphragmatic vagotomy suppressed the normal diurnal fluctuation of the enzyme activity, whereas hepatic sympathectomy tended to amplify the enzyme fluctuation. The result suggests that the diurnal fluctuation of cholesterogenic activity of the liver is under neural influences. Less