appetite Flashcards
gastrointestinal hormones and appetite: explain the role of gastrointestinal hormones in appetite regulation, with reference to their interaction with hypothalamic neural circuits
how many regulatory peptide hormones released by GIT
> 20
3 functions of gut hormones
influence processes including gut motility, secretion of other hormones and appetite
what is gut hormone release regulated by
gut nutrient content
GIT hormones and location
slide 35
what do enteroendocrine cells have, and what do these allow them to do
receptors on apical membrane; contain molecular machinery to respond to different food types (e.g. type of macromolecule, length etc.); release hormones from basal membrane for paracrine or endocrine effects, or to modulate neuronal function
what hormone is released from stomach, and 2 basic functions
ghrelin, involved in hunger and growth hormone release
ghrelin length and what attaches fatty acid chain to it
28 amino acids long; has faty acid chain attached by ghrelin O-acyltransferase
when does ghrelin have effect
decreases when food intaken, but steadily rises until eat again
how does ghrelin increase appetite, and effect on food intake
directly stimulates NPY/Agrp and inhibits POMC neurons, increasing food intake
2 gut hormones released by colon, and enteroendocrine cell they’re released from
GLP-1, PYY3-36 from L cells (apical membrane in contact with lumen of gut, with secretory granules near broad basal membrane; can also synapse with neurones)
what is GLP-1 involved in
incretin activity, satiation
what is PYY3-36 involved in
satiation
describe post-prandial secretion of PYY
goes up rapidly after heavy meals
how does PYY decrease appetite, and effect on food intake
directly inhibits NPY release and stimulates POMC neurons, reducing food intake
what gene codes for glucagon-like peptide-1 (GLP-1) and when is it released
coded for by preproglucagon gene, and released post-prandially
processing of pro-glucagon in intestinal L-cells
prohormone convertase 1 removes GLP-1 (active agonist) from pro-glucagon; quickly turned off by DP-IV which shortens half life (regulated by inactivation)
incretin roles of GLP-1
stimulates glucose-stimulated insulin release (possible treatment for type 2 diabetes), reduces food intake
GLP-1 as treatment of type 2 diabetes: modification
molecules bind to it to increase half-life, or to inhibit DP-IV so endogenous breakdown reduced
what is saxenda
long-acting GLP-1 receptor agonist (liraglutide) at double dose used for type 2 diabetes, causing weight loss
GIT hormones at treatment of obesity
all from L-cells so attempt to suppress appetite and food intake by targeting these
3 types of satiety action of gut hormones
post-prandial, chronic, acute nausea
purpose of post-prandial satiety action of gut hormones
reduces food intake following meal
chronic satiety action of gut hormones
gut disease, with chronic elevation suppressing appetite
acute nausea satiety action of gut hormones
toxin ingestions - acutely very high levels
gut hormones as drug targets to treat obesity byh reducing appetite
high dose will cause nausea, then drops quickly downt o no effect (only small peiod it is in useful effects of anorexigenic and increase glucose tolerance)
2 mechanisms of dietary manipulation
synthetic nutrients to stimulate nutrient receptors, deliver nutrients to specific regions of gut
