Mercer J G, Moar K M, Ross A W, Hoggard N, Morgan P J
Molecular Neuroendocrinology Unit, Aberdeen Centre for Energy Regulation and Obesity, Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, United Kingdom.
Am J Physiol Regul Integr Comp Physiol. 2000 Jan;278(1):R271-81. doi: 10.1152/ajpregu.2000.278.1.R271.
Siberian hamsters decreased body weight by 30% during 18 wk in short day (SD) vs. long day (LD) controls. Subsequent imposed food deprivation (FD; 24 h) caused a further 10% decrease. In the hypothalamic arcuate nucleus (ARC), SDs reduced proopiomelanocortin (POMC) gene expression and agouti-related protein (AGRP) mRNA was elevated, changes that summate to reduced catabolic drive through the melanocortin receptors. There was no effect of photoperiod on neuropeptide Y (NPY), melanin concentrating hormone, orexin, or corticotropin-releasing factor mRNAs. Superimposed FD increased AGRP gene expression and caused a localized elevation of NPY mRNA in the ARC. Both adipose tissue leptin and ARC leptin receptor (OB-Rb) mRNAs were downregulated in SDs, whereas FD increased OB-Rb gene expression. Thus OB-Rb mRNA is differentially regulated by acute and chronic changes in plasma leptin in this species. In a separate experiment in LDs, AGRP gene expression was increased by 24 or 48 h FD, whereas POMC mRNA was downregulated in the caudal ARC. AGRP and NPY mRNAs were extensively coexpressed in the ARC, and their differential regulation by photoperiod and FD is suggestive of transcript-specific regulation at the level of individual neurons.
与长日照（LD）对照组相比，西伯利亚仓鼠在短日照（SD）条件下18周内体重下降了30%。随后施加的食物剥夺（FD；24小时）导致体重进一步下降10%。在下丘脑弓状核（ARC）中，短日照降低了阿黑皮素原（POMC）基因表达，而刺鼠相关蛋白（AGRP）mRNA升高，这些变化共同导致通过黑皮质素受体的分解代谢驱动力降低。光周期对神经肽Y（NPY）、黑色素浓缩激素、食欲素或促肾上腺皮质激素释放因子mRNA没有影响。叠加的食物剥夺增加了AGRP基因表达，并导致ARC中NPY mRNA局部升高。在短日照条件下，脂肪组织瘦素和ARC瘦素受体（OB-Rb）mRNA均下调，而食物剥夺增加了OB-Rb基因表达。因此，在该物种中，OB-Rb mRNA受血浆瘦素急性和慢性变化的差异调节。在长日照条件下的另一项实验中，24或48小时的食物剥夺增加了AGRP基因表达，而尾侧ARC中的POMC mRNA下调。AGRP和NPY mRNA在ARC中广泛共表达，它们受光周期和食物剥夺的差异调节表明在单个神经元水平上存在转录本特异性调节。
