Monjo Marta, Pujol Esperanza, Roca Pilar
Departament de Biologia Fonamental i Ciències de la Salut, Institut Universitari d'Investigació en Ciències de la Salut, Universitat de les Illes Balears, Cra. Valldemossa, Km 7.5, Palma de Mallorca, 07122, Spain.
Am J Physiol Endocrinol Metab. 2005 Jul;289(1):E145-50. doi: 10.1152/ajpendo.00563.2004. Epub 2005 Feb 15.
Sex steroid hormones are important factors in the determination of fat distribution and accumulation. The aim of this study was to investigate the effect of testosterone (T), 17beta-estradiol (17betaE), and progesterone (P) on adrenergic receptor (AR) gene expression in 3T3-L1 preadipocytes and adipocytes and their relation to the proliferation and differentiation processes. Our data clearly show that alpha(2A)-AR was the highest AR subtype expressed in preadipocytes, whereas in mature adipocytes was by far beta(3)-AR. In the differentiation process to adipocytes, alpha(2A)-AR expression was decreased to 0.3-fold (P < 0.01), whereas beta(3)-AR was upregulated 578-fold (P < 0.001) compared with preadipocytes. In addition, the expression of alpha(2A)-AR in preadipocytes was increased upon incubation with T, 17betaE, and P, and a stimulation of proliferation was also observed in 17betaE- and P-treated cells. In mature adipocytes, 17betaE and P enhanced both alpha(2A)- and beta(3)-AR gene expression (although the effects on beta(3)-AR mRNA levels could be more relevant, since beta(3)-AR was the most highly expressed), whereas T only increased alpha(2A)-AR mRNA levels. Leptin and adipocyte fatty acid-binding protein mRNA levels were higher after 17betaE and P treatment, possibly indicating a proadipogenic effect of these hormones. In conclusion, this study indicates that AR gene expression is affected by these hormones in both preadipocytes and adipocytes, which could have potential importance when considering the role of ARs in the mechanisms underlying the sex-related differences in adipose tissue regional distribution.
性类固醇激素是决定脂肪分布和蓄积的重要因素。本研究旨在探讨睾酮（T）、17β-雌二醇（17βE）和孕酮（P）对3T3-L1前脂肪细胞和脂肪细胞中肾上腺素能受体（AR）基因表达的影响及其与增殖和分化过程的关系。我们的数据清楚地表明，α(2A)-AR是前脂肪细胞中表达最高的AR亚型，而在成熟脂肪细胞中，β(3)-AR的表达量占绝对优势。在向脂肪细胞的分化过程中，与前脂肪细胞相比，α(2A)-AR的表达量下降至0.3倍（P<0.01），而β(3)-AR上调了578倍（P<0.001）。此外，前脂肪细胞与T、17βE和P孵育后，α(2A)-AR的表达增加，并且在17βE和P处理的细胞中也观察到增殖受到刺激。在成熟脂肪细胞中，17βE和P增强了α(2A)-AR和β(3)-AR基因的表达（尽管对β(3)-AR mRNA水平的影响可能更显著，因为β(3)-AR是表达最高的），而T仅增加了α(2A)-AR mRNA水平。17βE和P处理后，瘦素和脂肪细胞脂肪酸结合蛋白的mRNA水平升高，这可能表明这些激素具有促脂肪生成作用。总之，本研究表明，这些激素会影响前脂肪细胞和脂肪细胞中AR基因的表达，这在考虑AR在脂肪组织区域分布性别差异潜在机制中的作用时可能具有重要意义。
