Atrens D M, Menéndez J A
Department of Psychology, University of Sydney, NSW, Australia.
Brain Res. 1993 Dec 10;630(1-2):238-44. doi: 10.1016/0006-8993(93)90662-7.
The effects of somatostatin injections (0.1, 1 and 5 micrograms) into the paraventricular nucleus of the hypothalamus (PVN) were investigated in an open-circuit calorimeter. Wistar rats were tested, with no food available during the tests. The 0.1 and 1 microgram doses produced large and long-lasting decreases in respiratory quotient, which indicates the preferential utilization of fats as an energy substrate. The 5 micrograms dose produced a brief decrease in energy expenditure. Locomotor activity was not affected by any treatment which indicates that the effects on respiratory quotient and energy expenditure are not secondary to changes in activity. These findings demonstrate that somatostatin in the PVN inhibits thermogenesis and induces the preferential utilization of fats while sparing carbohydrate reserves. However, it is significant that the effects on energy expenditure and energy substrate utilisation occurred at different doses. These data constitute the first evidence that somatostatin in the PVN produces a primary modulation of the metabolic parameters central to energy balance. In separate experiments, all three doses of somatostatin increased blood glucose concentration over a one hour period, and the 5 micrograms dose decreased body weight over a 24 h period. Food and water intake were not affected by the somatostatin injections. Taken together, these findings are interpreted in a model in which somatostatin is a signal to the PVN of increased body fat. This mobilizes sympathetic mechanisms which increase fat utilization and blood glucose levels.
在下丘脑室旁核（PVN）注射生长抑素（0.1、1和5微克）的效应在开路式热量计中进行了研究。使用Wistar大鼠进行测试，测试期间不给食物。0.1微克和1微克剂量可导致呼吸商大幅且持久下降，这表明优先利用脂肪作为能量底物。5微克剂量使能量消耗短暂下降。任何处理均未影响运动活动，这表明对呼吸商和能量消耗的影响并非继发于活动变化。这些发现表明，PVN中的生长抑素抑制产热，促使优先利用脂肪，同时节省碳水化合物储备。然而，重要的是，对能量消耗和能量底物利用的影响发生在不同剂量。这些数据首次证明，PVN中的生长抑素对能量平衡核心的代谢参数产生主要调节作用。在单独的实验中，所有三种剂量的生长抑素在一小时内均使血糖浓度升高，5微克剂量在24小时内使体重下降。生长抑素注射未影响食物和水的摄入量。综上所述，这些发现可在一个模型中进行解释，即生长抑素是向PVN发出的身体脂肪增加的信号。这会调动交感神经机制，从而增加脂肪利用和血糖水平。
