Kotz C M, Grace M K, Briggs J E, Billington C J, Levine A S
Department of Food Science and Nutrition, University of Minnesota, Saint Paul 55108, USA.
Am J Physiol. 1996 Jul;271(1 Pt 2):R289-94. doi: 10.1152/ajpregu.1996.271.1.R289.
Neuropeptide Y (NPY) has potent effects on several components of energy metabolism, including increased feeding and decreased brown fat thermogenesis. Negative energy balance, such as food deprivation, increases NPY mRNA in hypothalamic arcuate nucleus (ARC). Naltrexone (NLTX), an opioid receptor antagonist, decreases NPY-induced feeding. We hypothesized that NLTX would alter ARC NPY mRNA and change NPY effects on brown fat. Osmotic minipumps prefilled with either saline or NLTX (70 micrograms/h) were implanted subcutaneously in 32 male Sprague-Dawley rats. One-half of the rats were food deprived and one-half were allowed food ad libitum for 48 h. Food intake was measured at 24 and 48 h. At 48 h, ARC NPY mRNA and brown fat uncoupling protein (UCP) mRNA levels were determined using cDNA probes. Forty-eight-hour food intake was significantly decreased by 24% after NLTX infusion. Food deprivation and NLTX treatment significantly and independently increased ARC NPY mRNA and decreased UCP mRNA levels in brown fat, suggesting a complex interaction between hypothalamic NPY and endogenous opioids in the regulation of energy balance.
神经肽Y（NPY）对能量代谢的多个组成部分具有强大作用，包括增加进食和降低棕色脂肪产热。负能量平衡，如食物剥夺，会增加下丘脑弓状核（ARC）中的NPY mRNA。纳曲酮（NLTX），一种阿片受体拮抗剂，可减少NPY诱导的进食。我们假设NLTX会改变ARC中的NPY mRNA，并改变NPY对棕色脂肪的作用。将预先填充有生理盐水或NLTX（70微克/小时）的渗透微型泵皮下植入32只雄性Sprague-Dawley大鼠体内。其中一半大鼠进行食物剥夺，另一半大鼠自由进食48小时。在24小时和48小时测量食物摄入量。在48小时时，使用cDNA探针测定ARC中的NPY mRNA和棕色脂肪解偶联蛋白（UCP）mRNA水平。输注NLTX后，48小时的食物摄入量显著降低了24%。食物剥夺和NLTX处理显著且独立地增加了ARC中的NPY mRNA，并降低了棕色脂肪中的UCP mRNA水平，这表明下丘脑NPY和内源性阿片类物质在能量平衡调节中存在复杂的相互作用。
