16 - Genetic approaches to studyin energy balance, Barsh, G.S.

16 - Genetic approaches to studyin energy balance, Barsh, G.S.

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Article #15 – Genetic Approaches to Studying Energy Balance: Perception and Integration arcurate nucles (ARC) has specific neurons that act as sensors of whole-body energy status and initiate downstream responses to maintain fuel stores Neuronal contributions to various bodily functions could be localized to discrete brain regions – supported by lesioning studies LHA = hunger, VMN = satiety neuropeptide Y (NPY) o discovered in 1982 – neurons throughout brain but concentrated in ARC in hypothalamus o causes increase in food intake o Hypothalamic mediator of feeding behaviour, induced by changes in leptin (released from adipose tissue and its plasma concentration indicates body fat stores) signaling increase in leptin causes reduction in food intake and decrease in arcurate NPY mRNA levels α-MSH (-melanocyte stimulating hormone): o Endocrine hormone released from pituitary o Neuropeptide that regulates energy homeostasis o Produced by post-translational cleavage of POMC (found in same neurons as CART) o A melanocortin, inhibits feeding AGRP: o Expressed in same neurons in ARC as NPY o Only found in ARC o expression of Agrp in the arcurate nucleus increases in response to fasting of genetic leptin deficiencies o activates Npy neurons and inhibit melanocortin receptors increase food intake ARC (arcurate nucleus): o Two adjacent groups of cells – Agrp/Npy and Pomc/Cart – receive signals
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This note was uploaded on 03/18/2012 for the course BIO 3UU3 taught by Professor Dr.rollo during the Spring '12 term at McMaster University.

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16 - Genetic approaches to studyin energy balance, Barsh, G.S.

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