Oku Hiromi, Tokuda Masaharu, Okumura Takuji, Umino Tetsuya
National Research Institute of Aquaculture, Minami-ise, Mie, 516-0193, Japan.
Comp Biochem Physiol B Biochem Mol Biol. 2006 Jul;144(3):326-33. doi: 10.1016/j.cbpb.2006.03.008. Epub 2006 Mar 29.
Various kinds of hormones including insulin, triiodothyronine (T(3)) and fat-soluble vitamins have been proposed as mediators of adipocyte differentiation in mammals. To investigate the factors which are responsible for fish adipocyte differentiation, we developed a serum-free culture system of stromal-vascular cells of red sea bream adipose tissue and examined the effects of bovine insulin, T(3), and fat-soluble vitamins (all-trans retinoic acid, retinyl acetate and 1,25-dihydroxyvitamin D(3)) on the differentiation-linked expression of the lipoprotein lipase (LPL) gene. As assessed by the increase in LPL gene expression after 3 day cultivation, like in mammalian adipocytes, insulin enhanced the adipocyte differentiation in a concentration-dependent manner. During 2 week cultivation, bovine insulin promoted lipid accumulation in differentiating adipocytes concentration-dependently until the terminal differentiation. These results indicate that the differentiation of fish adipocytes is inducible by insulin alone. T(3) alone had no effect but enhanced the differentiation-linked LPL gene expression in the presence of insulin. Fat-soluble vitamins, unlike in mammalian adipocytes, did not show any significant effects. The method developed in this study should be of interest for the characterization of factors involved in fish adipocyte differentiation.
包括胰岛素、三碘甲状腺原氨酸（T(3)）和脂溶性维生素在内的多种激素已被提出作为哺乳动物脂肪细胞分化的介质。为了研究负责鱼类脂肪细胞分化的因素，我们开发了一种真鲷脂肪组织基质血管细胞的无血清培养系统，并研究了牛胰岛素、T(3)和脂溶性维生素（全反式维甲酸、醋酸视黄酯和1,25-二羟基维生素D(3)）对脂蛋白脂肪酶（LPL）基因分化相关表达的影响。如通过培养3天后LPL基因表达的增加所评估的，与哺乳动物脂肪细胞一样，胰岛素以浓度依赖的方式增强了脂肪细胞的分化。在2周的培养过程中，牛胰岛素浓度依赖性地促进分化中的脂肪细胞中的脂质积累，直至终末分化。这些结果表明，鱼类脂肪细胞的分化仅由胰岛素诱导。单独的T(3)没有作用，但在胰岛素存在的情况下增强了分化相关的LPL基因表达。与哺乳动物脂肪细胞不同，脂溶性维生素没有显示出任何显著影响。本研究中开发的方法对于表征参与鱼类脂肪细胞分化的因素应该是有意义的。
