Appetite

Question 1

How is the hypothalamus involved in feeding

Answer 1

Integrates the peripheral satiety signals

Question 2

Name 6 things that the hypothalamus influences in order to regulate metabolic rate

Answer 2

• Pituitary function
• Feeding
• Stress response
• Water balance
• Sleep-wake cycle
• Thermoregulation

Question 3

What is the main centre for appetite regulation in hypothalamus

Answer 3

Arcuate nucleus

Question 4

What 2 systems make up the arcuate nucleus

Answer 4

NPY/ Agouti related peptide

Cocaine related transcript and pro-opiomelanocortin

Question 5

What % is BMI heriditable

Answer 5

30-70

Question 6

Where is agouti related peptide (AgRP) found

Answer 6

In the hypothalmus co-current with cells producing NPY

Question 7

Effect of insulin levels on AgRP?

Answer 7

Insulin causes drop in AgRP levels

Question 8

What is meant by orexigenis

Answer 8

Appetite stimulating

Question 9

What is meant by anorexigenic

Answer 9

Appetite inhibiting

Question 10

What molecules are orexigenic

Answer 10

NPY
AgRP
MCH

Question 11

What molecules are anorexigenic

Answer 11

POMC

CART

Question 12

What is Pomc

Answer 12

Proopiomelanocortin

Question 13

What does POMC modify to become? What is action of the modified molecule?

Answer 13

Melanocortins

Binds to metlanocortin receptors

Question 14

Give an example of melanocortin receptor

Answer 14

MCR4

Question 15

What happens to mice and humans who are deficient in POMC

Answer 15

Develop hyperphagia and obesity

Question 16

What is considered the predominant POMC derived product which controls energy balance

Answer 16

Alpha-melanocyte-stimulating-hormone

Question 17

In what percentage of the following groups is an MC4R mutation found

a) obese adults
b) obses children

Answer 17

a) 0.5-2.5%

b) 5%

Question 18

Is serotonin anorexigenic or orexigenic?

Answer 18

Anorexigenic

Question 19

Which receptors does serotonin/ 5HT act

Answer 19

Htr1b and HTr2c

Question 20

What happens when serotonin acts on its receptors

Answer 20

• Increases signalling from POMC neurones

- Decreases AgRP neuron signalling

Question 21

Where is ghrelin secreted from

Answer 21

Stomach

Question 22

Where are ghrelin receptors found

Answer 22

NPY neurons

Question 23

Action of ghrelin

Answer 23

Stimulates NPY

Increases food intake both directly and via vagal nerve

Question 24

Does PYY 3-36 inhibit or increase food intake

Answer 24

Inhibit

Question 25

Describe the process by which PYY 3-36 inhibits food intake

Answer 25

- PYY 3-36 synthesised in gut - PYY reaches hypothalamus - PYY inhibits NPY neurones and stimulates POMC neurones - Food intake declines

Question 26

Where is glucagon like peptide released from

Answer 26

L cells in the gut lining

Question 27

What is the action of GLP-1

Answer 27

Interacts to inhibit NpY and stimulates PoMC

Question 28

What receptor does PYY act on

Answer 28

Y2R receptor

Question 29

What is the action of PYY

Answer 29

Inhibits NpY and stimulates PoMC`

Question 30

What does CCK stand for

Answer 30

Cholecystokinin

Question 31

Where is CCK secreted from?

Answer 31

Type 1 enteroendocrine cells in duodenum and small intestine

Question 32

Does CCK supress or improve appetite

Answer 32

Supresses

Question 33

Where is the hormone leptin secreted from

Answer 33

Adipose tissue

Question 34

What two genetic defects to do with leptin have been identified

Answer 34

- Defective leptin [ob] | - Defective receptor [db]

Question 35

Describe the phenotype of ob/ob and db/db mice (9)

Answer 35

- Obese - Increased appetite - Insulin resistance and diabetes - Hyperlipidaemia - Hypertension - Hypothermia - Infertility - Over expression of orexigenics - Decreased expression of POMC

Question 36

What is the effect of leptin and insulin on AGRP levels

Answer 36

Decrease in AGRP levels

Question 37

What happens if you inject congenitally leptin deficient children with leptin

Answer 37

Normalisation of body weight and fat mass

Question 38

What controls level of malonyl CoA?

Answer 38

AMPK | Calcium regulated

Question 39

Effect of cannabinoids on appetite and consumption of food

Answer 39

Increase appetite and consumption of food

Question 40

What is the receptor for cannabinoids in the brain

Answer 40

CB1

Question 41

What is the impact of CB1 activity in hunger centre

Answer 41

Increases palatability of food