Fat cells help to control blood sugar and insulin levels, according to a new Beth Israel Deaconess Medical Center study. Previously, the research team used mice studies to show that fat cells use sugar to regulate healthy levels of glucose and insulin. Now they have discovered a gene called carbohydrate-responsive-element-binding protein-beta in fat cells that appears to be the key to this action. "If we change that one gene, that makes the animal more prone to or more protected from diabetes," says senior author Barbara Kahn. "Two things were surprising—first, that a lone gene could shift the metabolism of the fat cell so dramatically and then, that turning on this master switch selectively in adipose tissue is beneficial to the whole body." When glucose levels rise, the gene is able to make a more active version of itself that changes sugar molecules into fatty acids. The gene is also found in the liver, however in the liver the gene changes sugar into triglycerides and can lead to fatty liver disease. Obesity, however, blocks GLUT4, an important glucose transporter, so sugar is prevented from entering the fat cells, leading to insulin resistance, which can then lead to diabetes. In the current study, the researchers found that obese mice with five to 10 times the normal amount of GLUT4 had none of the problems associated with obesity, while another set of normal weight mice with no GLUT4 developed diabetes symptoms.
