Metabolic dysfunction of white adipose tissue (WAT) is considered to be underlying the comorbidities in obesity, including insulin resistance and tissue inflammation. Moreover, due to the expansion of WAT, local tissue hypoxia has been reported. Whether local tissue hypoxia underlies the metabolic de-arrangements and is the first step in initiation inflammation is questioned here. Desferrioxamine (DFO) is a chemical compound trapping free iron, thus leading to a reduction in oxygen availability within the body, which mimics hypoxia. Therefore, C57BL/6JOlaHsd wildtype male mice, aged 9 weeks, were fed purified low fat diet (BIOCLAIMS, Hoevenaars et al., Genes and Nutrition 2012) for 3 weeks to acclimatize, followed by 12 weeks a BIOCLAIMS high-fat diet (HFD), all at thermoneutrality (29 degrees C) to induce massive expansion of WAT without metabolic dysregulation (Hoevenaars et al., Mol Nutr Food Res 2014). Subsequently, mice were divided into different treatment groups: i) control group, ii) 5 days Desferrioxamine (DFO) daily injections (100 mg/kg body weight). Mice were killed by decapitation at the end of the experiment after 2 hour food removal at the start of the light phase. After sacrification, epididymal WAT was immediately dissected and snap frozen in liquid nitrogen. Total RNA was isolated, quantified and qualified, and subsequently used for global gene expression profiling using Agilent 8x60K microarrays.