Changes in glucose levels are known to directly alter gene expression. A number of previous studies have found that these effects are in part mediated by modulating the levels and the activity of transcription factors. We have investigated an alternative mechanism by which glucose might regulate gene expression by modulating levels of a transcriptional repressor. We have focused on Id2 which is a protein which indirectly regulates gene expression by sequestering certain transcription factors and preventing them from forming functional dimers. Id2 targets include the class-A bHLH transcription factors and the sterol regulatory element binding protein 1 (SREBP-1). We demonstrate that increases in glucose levels cause a rapid increase in levels of Id2 in J774.2 macrophages and a number of lines of evidence indicate this is via the hexosamine pathway as; (i) the effect of glucose requires glutamine (ii) the effect of glucose is mimicked by low levels of glucosamine, (iii) the glucose effect is inhibited by azaserine, an inhibitor of glutamine:fructose-6-phosphate amidotransferase (GFAT), and (iv) adenoviral mediated overexpression of GFAT increases levels of Id2. We go on to show that increases in Id2 can have functional effects on metabolic genes as Id2 blocked the SREBP1 induced induction of hormone sensitive lipase (HSL) promoter activity while Id2 alone does not modulate activity of the HSL promoter. In summary these studies define a new mechanism by which glucose uses the hexosamine pathway to regulate gene expression by increasing levels of a transcriptional repressor.