Department of Psychology, Reed College, 3203 SE Woodstock Blvd, Portland, OR 97202, USA.
Brain Res. 2011 Apr 18;1385:127-34. doi: 10.1016/j.brainres.2011.01.114.
The corticotropin releasing hormone-related ligand, urocortin-I (UcnI), suppresses food intake when injected into multiple hypothalamic and extrahypothalamic areas. UcnI also alters energy substrate utilization, specifically via enhanced fat oxidation as reflected in reductions in respiratory quotient (RQ). In the present study we compared the feeding and metabolic effects of ghrelin and NPY following pretreatment with UcnI. Direct PVN injections of NPY (50 pmol) and ghrelin (50 pmol) were orexigenic while UcnI (10-40 pmol) reliably suppressed food intake. Both ghrelin and NPY increased RQ, indicating enhanced utilization of carbohydrates and the preservation of fat stores. UcnI alone suppressed RQ responses. PVN UcnI attenuated the effects of both ghrelin and NPY on food intake and energy substrate utilization. While ghrelin (5 pmol) potentiated the effect of NPY (25 pmol) on RQ and food intake, these responses were inhibited by pretreatment with UcnI (10 pmol). In conclusion, PVN NPY and ghrelin stimulate eating and promote carbohydrate oxidation while inhibiting fat utilization. These effects are blocked by UcnI which alone suppresses appetite and promotes fat oxidation. Overall these findings are consistent with a possible interactive role of PVN NPY, ghrelin and urocortin in the modulation of appetite and energy metabolism.
促肾上腺皮质激素释放激素相关配体，孤啡肽-I（UcnI），当注射到多个下丘脑和下丘脑外区域时，会抑制摄食。UcnI 还会改变能量底物的利用，特别是通过增强脂肪氧化来反映呼吸商（RQ）的降低。在本研究中，我们比较了 UcnI 预处理后胃饥饿素和 NPY 的摄食和代谢作用。PVN 中直接注射 NPY（50pmol）和胃饥饿素（50pmol）是食欲刺激剂，而 UcnI（10-40pmol）则可靠地抑制摄食。胃饥饿素和 NPY 均增加了 RQ，表明碳水化合物的利用增加，脂肪储存得到了保护。UcnI 单独抑制 RQ 反应。PVN UcnI 减弱了 ghrelin 和 NPY 对摄食和能量底物利用的影响。虽然 ghrelin（5pmol）增强了 NPY（25pmol）对 RQ 和摄食的作用，但这些反应被 UcnI（10pmol）预处理所抑制。总之，PVN NPY 和 ghrelin 刺激进食并促进碳水化合物氧化，同时抑制脂肪利用。这些作用被 UcnI 阻断，而 UcnI 本身就可以抑制食欲并促进脂肪氧化。总的来说，这些发现与 PVN NPY、ghrelin 和孤啡肽在调节食欲和能量代谢中的可能相互作用一致。
