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Stress-level glucocorticoids increase fasting hunger and decrease cerebral blood flow in regions regulating eating
There is considerable overlap between the brain control of stress and the neural regulation of hunger and energy balance. The cortico-limbic striatal system may become dysregulated as a result of recurrent acute stressor exposure, increasing allostatic load (exposure to endocrine or neural responses), and impairment of the integration of postprandial homeostatic and hedonic signals. Bini et al. (2022) underscore the need to comprehend the brain pathways through which stress causes changes in hunger that might result in weight gain. to ascertain the effects of glucocorticoids on the metabolic, neurological, and behavioral elements that may be responsible for the relationship between glucocorticoids, hunger, and the risk of obesity. To measure regional cerebral blood flow (CBF), the authors conducted a randomized, double-blind, cross-over study with hydrocortisone or saline overnight infusion followed by a fasting morning perfusion magnetic resonance imaging. Flyers and online advertisements were used to enlist 16 healthy, slim people (Mean BMI = 22.4 ± 2.2 kg/m2, Mean age = 26.4 ± 6.7 years), whom were assessed for cortisol levels, metabolic hormones, and hunger on the Visual Analog Scale (VAS). Analysis of the results revealed that, In the hypothalamus and associated cortico-striatal-limbic areas, hydrocortisone dramatically reduced whole-brain voxel-based CBF responses compared to saline. Less reduction in CBF (hydrocortisone minus saline) in the medial OFC, medial brainstem and thalamus, left primary sensory cortex, and right superior and medial temporal gyrus predicted hydrocortisone-related increases in appetite. In comparison to saline CBF groups, hydrocortisone significantly increased appetite as measured by the VAS pre-scan, insulin, glucose, and leptin, but not other metabolic hormones. On the hydrocortisone day but not the saline day, hunger evaluations were also strongly correlated with plasma insulin levels. The authors conclude that specific brain networks of prefrontal, emotional, reward, motivation, sensory, and homeostatic regions that underlie control of food intake become affected by increased glucocorticoids at levels similar to those experienced during psychological stress, increasing fasting hunger and decreasing regional cerebral blood flow. [NPID: Cortisol, glucocorticoids, hunger, stress, fMRI]
Year: 2022
