Challet E, Le Maho Y, Malan A
Centre d'Ecologie et Physiologie Energétiques, Centre National de la Recherche Scientifique, Strasbourg, France.
Physiol Behav. 1995 Aug;58(2):257-64. doi: 10.1016/0031-9384(95)00001-y.
The ventromedial hypothalamus (VMH) is known to be involved in the regulation of energy metabolism but it may also modulate locomotor activity. Since prolonged fasting is marked by a succession of changes in energy utilization and locomotor activity, it was hypothesized that VMH may be a critical link controlling mobilization of energy stores and/or behavioral changes in response to fasting. To test this, the changes in rate of body mass loss, body content in lipid and protein, and wheel-running activity were studied in fasted nonobese rats with VMH electrolytic lesions. Secondary effects of VMH obesity were ruled out by postoperative restricted feeding. During fasting, VMH lesions impaired neither the overall lipid mobilization nor the late rise in daily body mass loss, concomitant with the increase in net proteolysis. Despite that the onset of this late stage of fasting was significantly delayed in VMH vs. sham-operated rats (13 +/- 1 vs. 8 +/- 1 days, respectively), the final amount of reserve lipids (3 g) was closely similar in both groups: this is the first experimental evidence of the hypothesis of a lipidic set-point. These results indicate that VMH is not a critical link controlling the time-course of utilization of energy reserves. The increase in diurnal (and total) daily wheel-running observed in fasted sham-operated rats still occurred in fasted VMH rats but was significantly reduced and delayed. VMH nuclei and/or associated fibers are therefore involved in the fasting-induced rise in diurnal activity.
腹内侧下丘脑（VMH）已知参与能量代谢的调节，但它也可能调节运动活性。由于长期禁食的特点是能量利用和运动活性发生一系列变化，因此推测VMH可能是控制能量储备动员和/或对禁食反应的行为变化的关键环节。为了验证这一点，研究了VMH电解损伤的禁食非肥胖大鼠的体重减轻率、脂质和蛋白质的身体含量以及轮转运动活性的变化。通过术后限制进食排除了VMH肥胖的继发效应。在禁食期间，VMH损伤既不损害总体脂质动员，也不损害每日体重减轻的后期增加，同时伴随着净蛋白水解的增加。尽管VMH大鼠与假手术大鼠相比，禁食后期的开始明显延迟（分别为13±1天和8±1天），但两组的最终储备脂质量（3克）非常相似：这是脂质设定点假说的第一个实验证据。这些结果表明，VMH不是控制能量储备利用时间进程的关键环节。在禁食的假手术大鼠中观察到的昼夜（和总）每日轮转运动增加在禁食的VMH大鼠中仍然出现，但明显减少和延迟。因此，VMH核和/或相关纤维参与了禁食诱导的昼夜活动增加。
