A hormone that maintains metabolic health can improve insulin action in obese, diabetic mice, paving the way for new therapies to treat type 2 diabetes, scientists say. Andrew Butler, professor of pharmacological and physiological science at Saint Louis University, and his lab discovered the peptide hormone adropin several years ago. Adropin regulates whether the body burns fat or sugar during feeding and fasting cycles. "Adropin is a poorly understood hormone," Butler said. "We first reported its discovery a little over six years ago, but we really didn't understand what it did. We knew it played a role in maintaining metabolic health, but we didn't know much beyond that," he added. In a recent paper published in the journal Diabetes, Butler and team offered the first definition of adropin's functions that maintain metabolic health. "When we measured adropin levels in mice, they were suppressed under fasting conditions and stimulated after feeding, suggesting functions related to the changes in metabolism that occur with feeding and fasting," Butler said. "Our work suggests that adropin plays a role in regulating metabolic (energy) homeostasis," Butler added. "Basically, when you are well fed, your body prefers to use glucose and the release of adropin supports this change by enhancing the use of glucose as a metabolic fuel in muscle. "However, when you are fasting, your body prefers to use fatty acids. Our observations suggest that a decline in adropin with fasting may be a signal to "take the brakes off" the use of fatty acids," Butler said. Building on that work, researchers in a new paper in the journal Molecular Metabolism reported that low levels of the hormone observed in obesity may contribute to diabetes and the reduced ability of the body to use glucose. The team found that treatment with adropin improved glucose tolerance, enhanced insulin action and improved metabolic flexibility toward glucose utilisation in situations of obesity and insulin resistance. "The hope is that adropin could someday be used in the clinic to help patients with type 2 diabetes control blood sugar levels and delay or prevent the development of the disease in at-risk individuals," Butler said.