Wang T, Hartzell D L, Rose B S, Flatt W P, Hulsey M G, Menon N K, Makula R A, Baile C A
Department of Animal Science, The University of Georgia, Athens 30602, USA.
Physiol Behav. 1999;65(4-5):839-48. doi: 10.1016/s0031-9384(98)00243-1.
Leptin is a hormone secreted by adipocytes, which plays an important role in the control of food intake and metabolic processes. In the current study, a dose-dependent relationship was shown between a bolus intracerebroventricular rat recombinant leptin administration and reductions in food intake and body weight in Sprague-Dawley rats. During the 24 h postinjection period, food intake was decreased by 24, 26, and 52% with 0.625, 2.5, and 10 microg of leptin, respectively. Body weight was reduced by 2, 3, and 5% at 24 h after leptin administration at the doses of 0.156, 2.5, and 10 microg, respectively. Furthermore, indirect calorimetry demonstrated that five daily i.c.v. injections of leptin resulted in an increase in heat production per unit of metabolic body size and fat oxidation by approximately 10 and 48%, respectively. In contrast, food-restricted rats that consumed the equivalent amount of food as leptin-treated rats for 5 days decreased their energy expenditure by 10%. Food restriction was found to decrease respiratory quotient in a similar pattern as the leptin administration. When ad lib feeding was resumed, food-restricted rats quickly recovered their normal food intakes, body weights, and metabolism. Conversely, leptin treatment has prolonged effects on body weight resulting from different metabolic responses than food restriction. Leptin not only suppresses food intake, but also enhances energy expenditure to reduce fat depots.
瘦素是一种由脂肪细胞分泌的激素，在控制食物摄入和代谢过程中发挥着重要作用。在当前研究中，在向Sprague-Dawley大鼠脑室内一次性注射大鼠重组瘦素后，发现食物摄入量和体重的降低与剂量存在依赖关系。在注射后的24小时内，分别注射0.625、2.5和10微克瘦素时，食物摄入量分别减少了24%、26%和52%。在分别注射0.156、2.5和10微克瘦素后24小时，体重分别降低了2%、3%和5%。此外，间接测热法表明，每天脑室内注射5次瘦素会使每单位代谢体重的产热和脂肪氧化分别增加约10%和48%。相比之下，连续5天摄入与瘦素处理大鼠等量食物的食物限制大鼠，其能量消耗降低了10%。发现食物限制与瘦素注射一样，会以类似的模式降低呼吸商。当恢复自由采食时，食物限制大鼠迅速恢复其正常的食物摄入量、体重和新陈代谢。相反，与食物限制不同，瘦素处理由于不同的代谢反应而对体重有长期影响。瘦素不仅抑制食物摄入，还增强能量消耗以减少脂肪储备。
