Bour S, Prévot D, Guigné C, Stolen C, Jalkanen S, Valet P, Carpéné C
Institut National de la Santé et de la Recherche Médicale, U586 INSERM, IFR 31, CHU Rangueil, Toulouse, France.
J Neural Transm (Vienna). 2007;114(6):829-33. doi: 10.1007/s00702-007-0671-2. Epub 2007 Apr 4.
Substrates of semicarbazide-sensitive amine oxidases (SSAO) stimulate glucose transport in adipocytes. To definitively demonstrate the involvement of SSAO in this insulin-like effect, glucose transport has been studied in fat cells from mice with a targeted deletion of AOC3, a gene encoding a SSAO called vascular adhesion protein-1. SSAO activity was present in white adipose tissues of wild type (WT) but was absent in AOC3KO mice. The SSAO-substrates benzylamine and methylamine were unable to stimulate hexose transport in adipocytes isolated from AOC3KO mice while they were active in WT adipocytes, especially in combination with vanadate. Impairment of amine-dependent glucose uptake was also observed with tyramine while there was no change in insulin responsiveness. These observations prove that the effects of exogenous or biogenic amines on glucose transport are not receptor-mediated but are oxidation-dependent. They also confirm that the major SSAO form expressed in mouse adipocytes is encoded by the AOC3 gene.
氨基脲敏感性胺氧化酶（SSAO）的底物可刺激脂肪细胞中的葡萄糖转运。为明确证明SSAO参与这种胰岛素样效应，对靶向缺失AOC3基因（编码一种名为血管黏附蛋白-1的SSAO）的小鼠脂肪细胞中的葡萄糖转运进行了研究。野生型（WT）小鼠的白色脂肪组织中存在SSAO活性，但AOC3基因敲除（AOC3KO）小鼠中不存在。SSAO底物苄胺和甲胺无法刺激从AOC3KO小鼠分离的脂肪细胞中的己糖转运，而它们在WT脂肪细胞中具有活性，尤其是与钒酸盐联合使用时。用酪胺也观察到胺依赖性葡萄糖摄取受损，而胰岛素反应性没有变化。这些观察结果证明，外源性或生物源性胺对葡萄糖转运的影响不是受体介导的，而是氧化依赖性的。它们还证实，小鼠脂肪细胞中表达的主要SSAO形式由AOC3基因编码。
