Metabolic Phenotyping of Adipocyte Differentiation

18 19 The 3T3-L1 murine cell line is a robust and widely used model for the study of 20 adipogenesis and processes occurring in mature adipocytes. The fibroblastic like cells 21 can be induced by hormones to differentiate into mature adipocytes. In this study, the 22 metabolic phenotype associated with differentiation of the 3T3-L1 cell line has been 23 studied using gas chromatography-mass spectrometry, H nuclear magnetic resonance 24 spectroscopy, liquid chromatography-mass spectrometry, direct infusion-mass 25 spectrometry and C substrate labeling in conjunction with multivariate statistics. The 26 changes in metabolite concentrations at distinct periods during differentiation have been 27 defined including alterations in the TCA cycle, glycolysis, the production of odd chain 28 fatty acids by α-oxidation, fatty acid synthesis, fatty acid desaturation, polyamine 29 biosynthesis and trans-esterification to produce complex lipids. The metabolic changes 30 induced during differentiation of the 3T3-L1 cell line were then compared to the 31 metabolic differences between preand post-differentiation primary adipocytes. These 32 metabolic alterations reflect the changing role of the 3T3-L1 cells during differentiation, 33 as well as possibly providing metabolic triggers to stimulate the processes which occur 34 during differentiation. 35 36