Metabolic analysis, the researchers said, found that a much lower level of 5-hydroxy-indoleacetic acid (5-HIAA), the main metabolite of the neurotransmitter serotonin, was associated with diabetes. Although serotonin is perhaps best known for mood regulation, it has multiple functions, including controlling the development and function of the pancreatic beta cells that make insulin. "A low level of serotonin or its byproducts could reduce insulin secretion, causing obese people to progress from insulin resistance to type 2 diabetes," Gumus Balikcioglu said.
In addition, she said the diabetic teenagers had significantly higher levels of three metabolites than nondiabetic participants did. Among these were metabolites related to dysfunction of mitochondria, the "power unit" of the cell responsible for converting food to energy, and defects of the mitochondrial respiratory chain, which also lead to decreased energy production.
"Validation of our findings in larger clinical trials could provide a new noninvasive approach to identification of biomarkers for metabolic risk in in both children and adults," she said. "More importantly, analysis of serotonin metabolism may provide new therapeutic targets for diabetes prevention and treatment."