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目的：通过锌对热应激大鼠垂体阿黑皮素原（ＰＯＭＣ）ｍＲＮＡ表达的影响研究，探讨锌对热应激大鼠的保护机理。方法：２０只ＳＤ雄性大鼠随机等分４组，即高锌高温暴露组（Ａ组）、中锌高温暴露组（Ｂ组）、低锌高温暴露组（Ｃ组）和正常锌室温对照组（Ｄ组）。在ＡＩＮ－９３Ｍ饲料配方基础上，以碳酸锌为锌源，配制成高锌、中锌、低锌和正常锌饲料，每公斤饲料锌含量测定值分别为９２．２ｍｇ、４５．６１ｍｇ、２１．７０ｍｇ和４５．６１ｍｇ。４组大鼠在室温下饲以相应饲料１４天后，将Ａ、Ｂ、Ｃ组大鼠置于高温室（Ｔｄｂ４０℃，Ｔｗｂ３０．８℃）中连续暴露３小时。用Ｎｏｒｔｈｅｒｎｂｌｏｔ杂交分析法（探针为地高锌标记的ＰＯＭＣｃＲＮＡ），观察垂体ＰＯＭＣｍＲＮＡ表达水平。结果：（１）高温应激可使大鼠垂体ＰＯＭＣｍＲＮＡ表达水平增高；（２）高锌摄入可使热应激大鼠垂体ＰＯＭ－ＣｍＲＮＡ表达水平升高，而低锌摄入则相反。结论：锌对热应激大鼠垂体ＰＯＭＣ基因有调控作用，作用环节可能在转录水平上
OBJECTIVE: To study the protective effect of zinc on heat stress-induced rat pituitary melanotropin (POMC) mRNA expression. Methods: Twenty male Sprague-Dawley rats were randomly divided into 4 groups: high zinc exposure group (group A), medium zinc exposure group (group B), low zinc exposure group (group C) and normal zinc temperature control group (Group D). Based on the AIN-93M feed formulation, zinc carbonate was used as the zinc source to prepare high zinc, medium zinc, low zinc and normal zinc feed. The zinc content of each feed was 92.2mg and 45.61mg, respectively. 70 mg and 45.61 mg. Four groups of rats were fed with the corresponding feed for 14 days at room temperature, and rats in groups A, B and C were continuously exposed for 3 hours in a high-temperature room (Tdb40 ° C, Twb30.8 ° C). Pituitary expression of POMC mRNA was observed by Northern blot hybridization assay (probe of zinc-labeled POMCcRNA). Results: (1) POMC mRNA expression in pituitary of rats increased under high temperature stress; (2) POM-CmRNA expression increased in pituitary of rats with heat stress and decreased in zinc intake. Conclusion: Zinc can regulate the POMC gene in heat-stressed rats pituitary, and the effect may be related to transcriptional level