Digby J E, Chen J, Tang J Y, Lehnert H, Matthews R N, Randeva H S
Warwick Medical School, Clinical Sciences Research Institute, University of Warwick, Gibbett Hill Road, Coventry CV4 7AL, UK.
J Endocrinol. 2006 Oct;191(1):129-36. doi: 10.1677/joe.1.06886.
Orexin-A and orexin-B, via their receptors orexin-1 receptor (OX1R) and orexin-2 receptor (OX2R) have been shown to play a role in the regulation of feeding, body weight, and energy expenditure. Adipose tissue also contributes significantly to the maintenance of body weight by interacting with a complex array of bioactive peptides; however, there are no data as yet on the expression of orexin components in adipose tissue. We, therefore, analyzed the expression of OX1R and OX2R in human adipose tissue and determined functional responses to orexin-A and orexin-B. OX1R and OX2R mRNA expression was detected in subcutaneous (s.c.) and omental adipose tissue and in isolated adipocytes. Protein for OX1R and OX2R was also detected in whole adipose tissue sections and lysates. Treatment with orexin-A, and orexin-B (100 nM, 24 h) resulted in a significant increase in peroxisome proliferator-activated receptors gamma-2 mRNA expression in s.c. adipose tissue (P < 0.05). Hormone sensitive lipase mRNA was significantly reduced in omental adipose tissue with orexin-A and orexin-B treatment (P < 0.05). Glycerol release from omental adipose tissue was also significantly reduced with orexin-A treatment (P < 0.05). These findings demonstrate for the first time the presence of functional orexin receptors in human adipose tissue and suggest a role for orexins in adipose tissue metabolism and adipogenesis.
食欲素A和食欲素B通过其受体食欲素1型受体（OX1R）和食欲素2型受体（OX2R），已被证明在进食、体重和能量消耗的调节中发挥作用。脂肪组织也通过与一系列生物活性肽相互作用，对维持体重有显著贡献；然而，目前尚无关于脂肪组织中食欲素成分表达的数据。因此，我们分析了OX1R和OX2R在人体脂肪组织中的表达，并确定了对食欲素A和食欲素B的功能反应。在皮下和网膜脂肪组织以及分离的脂肪细胞中检测到了OX1R和OX2R mRNA的表达。在整个脂肪组织切片和裂解物中也检测到了OX1R和OX2R的蛋白质。用食欲素A和食欲素B（100 nM，24小时）处理后，皮下脂肪组织中过氧化物酶体增殖物激活受体γ-2 mRNA的表达显著增加（P<0.05）。用食欲素A和食欲素B处理网膜脂肪组织后，激素敏感性脂肪酶mRNA显著降低（P<0.05）。用食欲素A处理后，网膜脂肪组织中甘油的释放也显著减少（P<0.05）。这些发现首次证明了人体脂肪组织中存在功能性食欲素受体，并提示食欲素在脂肪组织代谢和脂肪生成中发挥作用。
