l7 -ghrelin

  • Created by: BKW
  • Created on: 09-01-20 14:31
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  • L7 - Ghrelin
    • What is it?
      • Growth Hormone releasing peptide secreted by the gut
      • Plays a role in energy homeostasis
      • In rodents Ghrelin stimulates feeding and weight gain
        • Plasma ghrelin concentrations ^^^ during fasting and vvv soon after eating
      • Mediates it's effects by stimulating hypothalamic orexigenic neurones that enhance feeding eg NPY
      • In rodents it appears to act as peripheral hunger signal to promote appetite and fat growth
        • Faulconbridge et al injected ghrelin into rodents - ghrelin ^^^ food intake, time between injection and first meal vvv, ^^^  in average size of first meal
    • Ghrelin and humans
      • Ghrelin levels rise progressively between meals and fall after feeding
        • they track and induce hunger
      • Wren et al - study on 9 healthy pps IV ghrelin or saline - found Ghrelin ^^^ food intake and enhanced visual alalogue scores of hunger - shows it a potent hunger signal
        • pps know they get a meal so ghrelin rises knowing they get food
      • Cummings et al 6 male pps Measured ghrelin levels before spontaneously initiated meals - found pre meal ^^^ in ghrelin and hunger scores and ghrelin similar. - ghrelin plays role in meal initiation
      • Arosio et al - 6 healthy pps examined the effect of cephalic phase on ghrelin response to feeding found vvv in ghrelin after sham and real feed and n diff in patterns of response
        • the cephalic response to nutrient intake plays a role in the control of ghrelin secretion
          • cephalic phase = gastric secreton before food enters stomach
    • Ghrelin & obesity
      • plasma ghrelin concentrations are ^^^ in anorexia &vvv in obesity
      • Ghrelin levels fall after gastric bypass surgery
      • Plasma ghrelin concentrations are increased after weight loss induced by dieting
      • Plasma ghrelin levels are ^^^ in patients with Pradi Willi syndrome
      • Obese individuals fail to supress ghrelin secretion post-meal
        • English et al 13lean 10obese pps - looked at effects of test meal on plasma ghrelin concentrations
          • found fasting ghrelin ^^^ in lean subjects, plasma ghrelin vvv by 40%in lean subjects after meal but n change in circulating ghrelin in obese group
            • lack of ghrelin suppression in obese could = ^^^ food intake and be involved in obesity


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