Hormone linked to weight gain and metabolic issues with high-sugar diet

By Katherine Shagoury

Low levels of a circulating hormone called adropin predict increased weight gain and metabolic dysregulation during consumption of a high-sugar diet in a nonhuman primate model, according to a new study published in the Journal of Biological Chemistry.

Researchers from Saint Louis University in Missouri examined the plasma of 59 adult male rhesus macaques monkeys fed a high sugar diet.

Overall, consumption of the fructose diet produced a 10 percent gain in body weight and increases of fasting levels of insulin, indicating insulin resistance, which reduces glucose use and elevated fasting triglycerides, according to the study abstract. In humans, this increases the risk of cardiovascular disease.

Animals with low plasma adropin concentrations developed a more severe metabolic syndrome, the study said. Further, development of type 2 diabetes was only observed in animals with low plasma adropin concentrations. These animals also showed more pronounced dysregulation of glucose and lipid metabolism. Fasting hyperglycemia was also limited to animals with low circulating adropin, indicating glucose intolerance.

The team also examined a baboon transcriptome (genetic) data set to explore expression of the adropin gene in a nonhuman primate. Adropin is encoded by the Energy Homeostasis Associated (ENHO) gene.

The results are consistent with the idea that adropin expression is controlled via “clock-related” mechanisms. Every cell in the body maintains its own internal clock to control daily rhythms in metabolism. There is a growing awareness of the importance of the biological clocks that control the “circadian rhythm” in health and disease. The current finding suggests that adropin may link the biological clock to rhythms in the way the body uses sugar and fats as metabolic fuel.

In this way, stimulation of adropin expression by our internal clocks may contribute to increasing the use of glucose as a metabolic fuel during the daytime. Other findings show that adropin expression is co-regulated with clusters of genes involved in glucose and fat metabolism in the liver.

Obesity is a growing public health crisis, bringing with it many serious risk factors, including cardiovascular disease and type 2 diabetes. As the number of people who are either overweight or obese now outnumbers those with a healthy body weight by a ratio of two to one, researchers face an urgent need to better understand how the body burns fuel.

The researchers said they hope these findings will help set the stage to develop new therapies for managing metabolic diseases.