Evidence for a functional nitric oxide synthase system in brown adipocyte nucleus

FEBS Letters

Tonello, Cristina¹  Bulbarelli, Alessandra¹  Nisoli, Enzo¹  Carruba, Michele O¹  Giordano, Antonio²  Cinti, Saverio²  Cozzi, Valeria¹ 

[1] Center for Study and Research on Obesity, Department of Preclinical Sciences, LITA Vialba, L. Sacco Hospital, Faculty of Medicine, University of Milan, Via G.B. Grassi 74, 20157 Milan, Italy;Institute of Normal Human Morphology, Faculty of Medicine, University of Ancona, Ancona, Italy

关键词: Nitric oxide synthase;    Brown adipocyte;    Cell nucleus;    β3-adrenoceptor;    L-citrulline;   

DOI  :  10.1016/S0014-5793(02)02245-7

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The intracellular localization and activity of the nitric oxide synthase (NOS) isoforms were investigated in rat brown adipocytes. Immunohistochemistry showed cytoplasmic and nuclear staining for the endothelial NOS (eNOS) and inducible NOS (iNOS) isoforms; accordingly, anti-L-citrulline antibody, a marker of NOS activity, immunostained both the cytoplasm and the nucleus. The presence of metabolically active NOS in the nucleus was further confirmed by immunoblotting analyses of subcellular fractions of homogenates from cultured brown adipocytes and by measurements of NOS activity in the cytosol and nucleus. Sympathetic stimulation in vivo (i.e. cold exposure or β₃-adrenergic agonist treatment) and in vitro (i.e. noradrenaline treatment of cultured cells) significantly increased both cytosolic and nuclear eNOS and iNOS expression and activities. By contrast, the number of iNOS-positive, but not eNOS-positive, nuclei was significantly lower in the functionally impaired brown fat of genetically obese Zucker fa/fa rats. These data suggest the existence of a noradrenaline-modulated functional NOS system in the nucleus of brown adipocytes.

【 授权许可】

Unknown