Tissue-specific insulin sensitivity in anorexia nervosa: A cross-sectional positron emission tomography (PET) study...

Anorexia nervosa (AN) has been linked to both impaired and improved whole-body insulin sensitivity, but tissue-specific metabolic alterations remain unexplored. To address this gap, we studied 12 female volunteers with recently diagnosed AN and 13 healthy, lean female controls in a cross-sectional design using positron emission tomography (PET) imaging with the glucose analogue [¹⁸F]FDG tracer under hyperinsulinemic conditions. We show that tissue-specific glucose uptake during hyperinsulinemia was higher only in the duodenum of individuals with AN, but comparable in other tissues, possibly indicating altered intestinal glucose handling and nutrient sensing in reduced energy intake. In five participants with AN, glucose uptake was elevated despite reduced skeletal muscle glucose utilization. In controls, growth hormone (GH) levels correlated with skeletal muscle, liver, and brain insulin sensitivity, but these associations were absent in AN, suggesting disrupted endocrine regulation of glucose metabolism. Overall, whole-body insulin sensitivity was not altered, yet tissue-specific glucose metabolism exhibited greater variability in AN. These differences were not directly explained by disease duration or weight loss severity, suggesting contributions from individual genetic background and behavioral patterns.