BIOLOGY 3UU3 Lecture Notes - Lecture 2: Leptin Receptor, White Adipose Tissue, Insulin Receptor
26 Sep 2016
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Knockout of orexin= narcolepsy, loss of fasting induced forathing. Mice that don"t have da die of starvation, can be reversed. Orexins colocalized with mch in lha, mch also stim feeding and shares inputs form arc. Orexin up reg by low glucose, leptin, elevated npy and ghrelin singaling. Glut stim orexin neuron and stim feeding in lha. In ob/ob mouse, orix neurons express red activity, less locomotion, red body temp, increased sleep and higher efficiency to convert food to fat. Theory: gluc acts as appetite suppressor whereas low glucose stim feeding (homeostatic) Gluc utilisation likely fast, theory not explain everything, Signaling by liver (the site of glucose synthesis) via the vagus nerve may also be involved. Theory: fat mass homeostatically maintained via feedback to the hypothalamus indicative of the status of fat store. Glucose more available during waking period, fatty acids elevated in sleep. Insulin resistance in sleep so fatty acids are alt fuel.
