RATIONALE: Type-2 diabetes is a disease state that affects multiple organs of the biological system, including alterations in adipocyte and muscle insulin signalling, hepatic glucose production, glucose absorption from the gastrointestinal tract, and pancreatic insulin deficiency caused by the loss of β-cell mass and function. Understanding the molecular communication taking place both within and between these tissues is paramount to unravel the metabolic regulatory networks and mechanisms underlying diabetes. Global gene expression profiling (i.e. transcriptomics) and metabolite profiling (i.e. metabolomics) offer powerful approaches to understand the biological processes associated with diabetes and obesity. The analysis of gene expression profiles provides an opportunity to identify early markers of metabolic dysregulation. In contrast, metabolites represent an endpoint of gene and protein function; thus metabolomics is ideally suited for the identification of biomarkers that reflect the biochemical processes underlying a physiological state. By integrating gene expression profiling with metabolite profiling, we will have the opportunity to improve our understanding of the metabolic perturbations related to obesity and/or type-2 diabetes.