Rodriguez-Pacheco Francisca, Martinez-Fuentes Antonio J, Tovar Sulay, Pinilla Leonor, Tena-Sempere Manuel, Dieguez Carlos, Castaño Justo P, Malagon María M
Department of Cell Biology, Physiology and Immunology, University of Córdoba, E-14014 Córdoba, Spain.
Endocrinology. 2007 Jan;148(1):401-10. doi: 10.1210/en.2006-1019. Epub 2006 Oct 12.
Adiponectin is a member of the family of adipose tissue-related hormones known as adipokines, which exerts antidiabetic, antiatherogenic, antiinflammatory, and antiangiogenic properties. Adiponectin actions are primarily mediated through binding to two receptors expressed in several tissues, AdipoR1 and AdipoR2. Likewise, adiponectin expression has been detected in adipocytes as well as in a variety of extra-adipose tissues, including the chicken pituitary. Interestingly, adiponectin secretion and adiponectin receptor expression in adipocytes have been shown to be regulated by pituitary hormones. These observations led us to investigate whether adiponectin, like the adipokine leptin, regulates pituitary hormone production. Specifically, we focused our analysis on somatotrophs and gonadotrophs because of the relationship between the control of energy metabolism, growth and reproduction. To this end, the effects of adiponectin on both GH and LH secretion as well as its interaction with major stimulatory regulators of somatotrophs (ghrelin and GHRH) and gonadotrophs (GnRH) and with their corresponding receptors (GHS-R, GHRH-R, and GnRH-R), were evaluated in rat pituitary cell cultures. Results show that adiponectin inhibits GH and LH release as well as both ghrelin-induced GH release and GnRH-stimulated LH secretion in short-term (4 h) treated cell cultures, wherein the adipokine also increases GHRH-R and GHS-R mRNA content while decreasing that of GnRH-R. Additionally, we demonstrate that the pituitary expresses both adiponectin and adiponectin receptors under the regulation of the adipokine. In sum, our data indicate that adiponectin, either locally produced or from other sources, may play a neuroendocrine role in the control of both somatotrophs and gonadotrophs.
脂联素是一类被称为脂肪因子的脂肪组织相关激素家族的成员，具有抗糖尿病、抗动脉粥样硬化、抗炎和抗血管生成特性。脂联素的作用主要通过与几种组织中表达的两种受体AdipoR1和AdipoR2结合来介导。同样，在脂肪细胞以及包括鸡垂体在内的多种非脂肪组织中都检测到了脂联素的表达。有趣的是，脂肪细胞中的脂联素分泌和脂联素受体表达已被证明受垂体激素调节。这些观察结果促使我们研究脂联素是否像脂肪因子瘦素一样调节垂体激素的产生。具体而言，由于能量代谢、生长和繁殖的控制之间存在关系，我们将分析重点放在生长激素细胞和促性腺激素细胞上。为此，在大鼠垂体细胞培养物中评估了脂联素对生长激素（GH）和促黄体生成素（LH）分泌的影响，以及它与生长激素细胞（胃饥饿素和生长激素释放激素）和促性腺激素细胞（促性腺激素释放激素）的主要刺激调节因子及其相应受体（生长激素促分泌素受体、生长激素释放激素受体和促性腺激素释放激素受体）的相互作用。结果表明，在短期（4小时）处理的细胞培养物中，脂联素抑制GH和LH释放，以及胃饥饿素诱导的GH释放和促性腺激素释放激素刺激的LH分泌，其中该脂肪因子还增加生长激素释放激素受体和生长激素促分泌素受体的mRNA含量，同时降低促性腺激素释放激素受体的mRNA含量。此外，我们证明垂体在该脂肪因子的调节下表达脂联素和脂联素受体。总之，我们的数据表明，无论是局部产生还是来自其他来源的脂联素，可能在生长激素细胞和促性腺激素细胞的控制中发挥神经内分泌作用。
