Functional MRI of Hypothalamic Responses to Circulating Glucose and Fatty Acids
Hwang J, Rossetti L, Takahashi K, Miyasaka N, Nagaoka T, Sun W, Lam T
Albert Einstein College of Medicine
Hypothalamic sensing of circulating nutrients (e.g. glucose) has recently been implicated in regulation of glucose homeostasis. However, previous reports on hypothalamic activation induced by glucose intake have not addressed the relative contribution of hypothalamic glucose sensing and plasma insulin during hyperglycemia. The purpose of this fMRI study was to examine hypothalamic activation, isolated from changes in insulin levels, compared to the effect of fatty acids sensing, specifically by measuring R2* changes in rats. Glucose infusion resulted in localized R2* increase (T2* decrease) in the medial hypothalamic area. However, no significant localized activation was detected during systemic lipid infusion.