Occurrence of brown adipocytes in rat white adipose tissue: molecular and morphological characterization.
Occurrence of brown adipocytes in rat white adipose tissue: molecular and morphological characterization.
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发表时间：
1992-12
影响因子：
4
通讯作者：
B. Cousin;S. Cinti;M. Morroni;S. Raimbault;D. Ricquier;L. Pénicaud;L. Casteilla
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文献类型：
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作者：
B. Cousin;S. Cinti;M. Morroni;S. Raimbault;D. Ricquier;L. Pénicaud;L. Casteilla
棕色脂肪细胞是产热细胞，在能量平衡中发挥重要作用。它们的产热活性是由于线粒体解偶联蛋白（UCP）的存在。直到最近，人们才承认啮齿类动物的棕色脂肪细胞主要位于经典棕色脂肪组织（BAT）中。在本研究中，我们研究了大鼠白色脂肪组织 (WAT) 中 UCP 蛋白或 mRNA 的存在。使用聚合酶链反应或 Northern 印迹杂交，在肠系膜、附睾、腹膜后、腹股沟，特别是卵巢周围脂肪库中检测到 UCP mRNA。通过蛋白质印迹法在卵巢周围脂肪组织的线粒体中检测到解偶联蛋白。当大鼠接受寒冷或用β-肾上腺素受体激动剂治疗时，该组织中的UCP表达与典型的棕色脂肪中一样增加。此外，与瘦对照相比，肥胖 fa/fa 大鼠的表达降低。形态学研究表明，24℃保存的大鼠卵巢周围脂肪组织中含有大量典型BAT线粒体的细胞，有或没有多房脂滴。免疫细胞化学证实多房细胞表达线粒体UCP。此外，棕色脂肪细胞的数量和线粒体嵴的密度随着暴露于寒冷而增加。这些结果证明表达 UCP 的脂肪细胞存在于被视为白色脂肪的脂肪沉积物中。他们表明啮齿动物中 BAT 和 WAT 之间存在连续体，并且脂肪组织表型之间存在很大的可塑性。棕色脂肪细胞在 WAT 中的生理重要性和 UCP 表达的调节仍然是一个悬而未决的问题。
Brown adipocytes are thermogenic cells which play an important role in energy balance. Their thermogenic activity is due to the presence of a mitochondrial uncoupling protein (UCP). Until recently, it was admitted that in rodents brown adipocytes were mainly located in classical brown adipose tissue (BAT). In the present study, we have investigated the presence of UCP protein or mRNA in white adipose tissue (WAT) of rats. Using polymerase chain reaction or Northern blot hybridization, UCP mRNA was detected in mesenteric, epidydimal, retroperitoneal, inguinal and particularly in periovarian adipose depots. The uncoupling protein was detected by Western blotting in mitochondria from periovarian adipose tissue. When rats were submitted to cold or to treatment with a beta-adrenoceptor agonist, UCP expression was increased in this tissue as in typical brown fat. Moreover, the expression was decreased in obese fa/fa rats compared to lean controls. Morphological studies showed that periovarian adipose tissue of rats kept at 24 degrees C contained cells with numerous typical BAT mitochondria with or without multilocular lipid droplets. Immunocytochemistry confirmed that multilocular cells expressed mitochondrial UCP. Furthermore, the number of brown adipocytes and the density of mitochondrial cristae increased in parallel with exposure to cold. These results demonstrate that adipocytes expressing UCP are present in adipose deposits considered as white fat. They suggest the existence of a continuum in rodents between BAT and WAT, and a great plasticity between adipose tissue phenotypes. The physiological importance of brown adipocytes in WAT and the regulation of UCP expression remain open questions.