Brandebourg T, Hugo E, Ben-Jonathan N
Department of Cell Biology, University of Cincinnati School of Medicine, Cincinnati, OH, USA.
Diabetes Obes Metab. 2007 Jul;9(4):464-76. doi: 10.1111/j.1463-1326.2006.00671.x.
Pituitary-derived prolactin (PRL) is a well-known regulator of the lactating mammary gland. However, the recent discovery that human adipose tissue produces PRL as well as expresses the PRL receptor (PRLR) highlights a previously unappreciated action of PRL as a cytokine involved in adipose tissue function. Biologically active PRL is secreted by all adipose tissue depots examined: breast, visceral and subcutaneous. The expression of adipose PRL is regulated by a non-pituitary, alternative superdistal promoter. PRL expression and release increases during early pre-adipocyte differentiation and is stimulated by cyclic AMP activators, including beta adrenergic receptor agonists. PRL release from subcutaneous adipose explants is attenuated during obesity, suggesting that adipose PRL production is altered by the metabolic state. Several lines of evidence indicate that PRL suppresses lipid storage as well as the release of adipokines such as adiponectin, interleukin-6 and possibly leptin. PRL has also been implicated in the regulation of adipogenesis. A newly developed PRL-secreting human adipocyte cell line, LS14, should allow comprehensive examination of the regulation and function of adipocyte-derived PRL. Collectively, these studies raise the prospect that PRL affects energy homeostasis through its action as an adipokine and is involved in the manifestation of insulin resistance.
垂体分泌的催乳素（PRL）是泌乳乳腺的一种众所周知的调节因子。然而，最近发现人类脂肪组织也能产生PRL并表达PRL受体（PRLR），这凸显了PRL作为一种参与脂肪组织功能的细胞因子，其作用此前未被充分认识。所有检测的脂肪组织库（乳腺、内脏和皮下）都会分泌生物活性PRL。脂肪组织PRL的表达由一个非垂体的替代性超远端启动子调控。在脂肪前体细胞早期分化过程中，PRL的表达和释放会增加，并受到环磷酸腺苷激活剂（包括β肾上腺素能受体激动剂）的刺激。肥胖期间，皮下脂肪外植体中PRL的释放会减弱，这表明脂肪组织中PRL的产生会因代谢状态而改变。多项证据表明，PRL可抑制脂质储存以及脂联素、白细胞介素-6甚至可能还有瘦素等脂肪因子的释放。PRL还与脂肪生成的调节有关。新开发的分泌PRL的人类脂肪细胞系LS14，应该能够全面研究脂肪细胞来源的PRL的调节和功能。总体而言，这些研究提出了一种可能性，即PRL通过作为脂肪因子发挥作用来影响能量平衡，并参与胰岛素抵抗的表现。
