糖皮质激素对肥胖大鼠和普通大鼠下丘脑神经肽Y mRNA的影响

目的:研究糖皮质激素对肥胖大鼠和普通大鼠下丘脑中神经肽Y(neuropeptide Y,NPY)mRNA表达的影响。方法:高脂饲料构建肥胖大鼠模型,肥胖大鼠和普通大鼠分别随机分为生理盐水组、小剂量组和大剂量组,分别连续20天腹腔注射生理盐水0.2 ml/100 g、琥珀酸氢化可的松5 mg/kg和15 mg/kg。并观察其摄食变化,用实时荧光定量PCR方法,检测大鼠下丘脑中NPY mRNA的表达水平。结果:应用大剂量糖皮质激素后普通大鼠和肥胖大鼠的摄食量低于盐水组(P<0.05);应用大剂量糖皮质激素后普通大鼠和肥胖大鼠的下丘脑中NPY mRNA的表达水平低于盐水组(P<0.01);应用小剂量糖皮质激素后普通大鼠的下丘脑中NPY mRNA的表达水平低于盐水组(P<0.01)。结论:大剂量糖皮质激素使普通大鼠和肥胖大鼠食欲下降,抑制肥胖大鼠和普通大鼠NPY mRNA的表达;小剂量糖皮质激素抑制普通大鼠NPY mRNA的表达,NPY在食欲调节中起重要作用。

Influence of glucocorticoids on neuropeptide Y mRNA expression in hypothalamus of obese and nonobese rats

Objective：To investigate the effects of glueoeortieoid on neuropeptide Y （NPY） gene expression of the hypothalamus in obese and nonobese rats. Methods：Obese rat model was established by high-fat diet. Both the obese and nonobese rats were randomly assigned to normal saline（NS） group,low dose and high dose of glueocorlicoid groups,and were administered intraperitoneal injection with normal saline 0.2 ml/100 g, hydroeortisone sodium sueeinate 5 mg/kg and 15 mg/kg,respeetively, for 20 days. Their food intake was measured. Ileal-time quantilatixe PCR was used to measure the expression of NPY mRNA in the hypothalamus of the rats. Results： After high dose of glucoeortieoid injection,the food intake of the obese and nonobese rats was lower than that of the NS group （ P 〈 0.05） ; the mRNA expressions of NP5 in the hypothalamus of the obese and nonobese rats was lower than that of the NS group（ P 〈 0.01 ） ; the expression of NPY mRNA of the nouobese rats in the low dose group was significantly lower than that of the NS group （P 〈0.01 ）. Conclusions： ttigh dose of glucoeorticoid may inhibit the appetite and the NPY mRNA expression in the hypothalamus of the obese and nonobese rats; low dose of glucocortieoid can inhibit the NPY mRNA expression in the hypothalamus of nonobese rats. NPY plays an importanl role in regulation of the appetite of rats.