GI Appetite Hormones

Question 1

hypothalamus eating centers

Answer 1

feeding center (lat): stim appetite
satiety center (ven): decrease appetite

Question 2

Appetite hormones

Answer 2

ghrelin (up)
CCK (down)
glucagon-like peptide (GLP-1) (down)
peptide YY3-36 (PYY3-36) (down)

Question 3

ghrelin made by

Answer 3

cells in stomach, SI, hypothalamus

Question 4

ghrelin release stimulated by

Answer 4

goes up: before meals

goes down: after eating (esp protein). carbs are temporary.

Question 5

ghrelin levels in obese/anorexic

Answer 5

decrease is absent or blunted w/ obesity

anorexics have chronically high ghrelin - ignore it

Question 6

CCK made by

Answer 6

cells in duodenum and jejunum

Question 7

CCK release stimulated by

Answer 7

respond to stretch/distension in GI nerves

Question 8

CCK effect on brain

Answer 8

short-lived satiety

Question 9

ghrelin effect on brain

Answer 9

increase appetite

Question 10

GLP-1 made by

Answer 10

ileal L cells

Question 11

GLP-1 stimulated by

Answer 11

nutrients in lumen of SI

Question 12

GLP-1 actions

Answer 12

stim glucose dependent insulin secretion
suppress glucagon secretion
inhibit gastric secretion (delays absorption of carbs - makes you feel satiated)

Question 13

PYY3-36 made by

Answer 13

L cells in SI/LI

Question 14

PYY3-36 stim by

Answer 14

after meals

Question 15

PYY3-36 actions

Answer 15

bind to NPY receptor (inhibit NPY secretion)
reduce appetite
inhibit gastric motility

Question 16

NPY actions

Answer 16

up food intake
up fat storage
reduce anxiety/stress
reduce pain perception

Question 17

NPY levels/times

Answer 17

high before meal and high as long as food is w/held

Question 18

NPY stimulated by

Answer 18

low: leptin, insulin, PYY
high: ghrelin
(like it is while fasting)

Question 19

agouti-related peptide (AgRP)

Answer 19

antagonist of alpha-MSH

Question 20

agouti-related peptide actions

Answer 20

increase appetite

Question 21

orexigenic factors

Answer 21

increase food consumption
NPY
AgRP

Question 22

anorexigenic factors

Answer 22

decrease food consumption

leptin

Question 23

leptin stimulated by

Answer 23

levels proportional to body fat

Question 24

leptin actions

Answer 24

act on hypothalamus receptors
inhibit appetite (long-term)
"starvation signal" to maintain adequate fat

Question 25

absence of leptin –>

Answer 25

uncontrolled food intake and obesity

Question 26

leptin resistance mech

Answer 26

usually: feast –> up leptin –> down appetite
fattys: feast all the time –> up leptin –> down regulare receptors –> less regulation of appetite

Question 27

insulin and leptin

Answer 27

insulin is leptin-antagonist
chronically high insulin blocks leptin signaling
why? @ puberty/pregnancy need to gain weight - hyperinsulinemic states

Question 28

chronic cortisol levels

Answer 28

up food intake
down leptin
up ghrelin
+ makes you store fat in belly

Question 29

endocannabinoid (EC) comes from

Answer 29

PHL in cell membranes

esp omega-6 FAs

Question 30

EC actions

Answer 30

bind to CB-1 receptors –>
brain: stim caloric intake
liver, AT, skeletal muscle, GI: form and store lipids

Question 31

EC and obesity

Answer 31

if EC system is overactivated –> weight gain, lipogenesis

Question 32

blocking CB-1

Answer 32

EC's cant bind
down food consumption
up weight loss
down body fat
problem: suicidal tendencies

Question 33

satiety vs continuing a meal

Answer 33

satiety signals make GABA released from pre-synaptic neurons to inhibit postsynaptic neuron from continuing the meal
blocked by palatable food, pleasing social, etc –> Ca up –> up EC (bind to CB1 on pre-synaptic) –> down GABA –> keep eating

Question 34

alpha-MSH actions

Answer 34

stim satiety