Role of the GIT in Obesity Flashcards Preview

Metabolism > Role of the GIT in Obesity > Flashcards

Flashcards in Role of the GIT in Obesity Deck (54):
1

Weight is regulated in the

Hypothalamus

2

Which nucleus in the hypothalamus regulates body weight?

Arcuate nucleus

3

What are the two classes of nerves in the arcuate nucleus?

NPY (NPY and AgRP)
POMC (CART and aMSH)

4

NPY nerves release _______ when they fire which ________ appetite

NPY and agouti-related protein (AgRP); increase appetite

5

POMC nerves release ________ when they fire which _________ appetite

CART (cocaine and amphetamine related transcript) and aMSH; decrease appetite

6

Which hormones from the stomach regulate food intake at the arcuate nucleus?

Ghrelin

7

Which hormones from the small bowel regulate food intake at the arcuate nucleus?

CCK, PYY, GLP-1, Oxyntomodulin, Uroguanilin

8

Which hormones from the pancreas regulate food intake at the arcuate nucleus?

insulin, amylin, PP

9

Ghrelin ________ appetite by activating _______

increases; NPY and its mRNA

10

Leptin ________ appetite

decreases;

11

Ghrelin and leptin work

antagonistically

12

Ghrelin rises _________ and drops __________

before a meal; after a meal - diurnal variation

13

ILP-5 ________ appetite via ________

increases; relaxin5 receptor (GPCR)

14

ILP-5 is expressed

colon; less so in ileum, none in jejunum

15

Which hormone is the most powerful driver of hunger?

NPY > Ghrelin > ILP-5

16

CCK is made in the

upper bowel/I cells of small intestine

17

CCK is made as a

preprohormone

18

Which CCK peptide has the highest potency?

CCK8

19

CCK is secreted from

I cells in small intestine

20

The half-life of CCK is

short (~mins)

21

CCK stimulates

emptying of the gallbladder and release of digestive enzymes

22

CCK acts through which receptors?

CCK1 and CCK2

23

CCK _________ food intake and is involved in _________

inhibits; digestion

24

CCK mediates its effects mainly via

CCK1R on the vagus nerve

25

Why doesn't CCK work as a tx in obesity?

Reduces food intake but increases number of meals

26

PYY is made in the

L cells of the GIT (ileum)

27

PYY ________ food intake and _______ body weight

reduces; decreases (chronic)

28

PYY is cleaved by

DPP4; the enzyme that degrades GLP-1, oxyntomodulin

29

What is the action of PYY?

reduces food intake (and body weight if used chronically); increases feelings of satiety (but also nausea)

30

Oxyntomodulin is a product of which gene?

Glucagon

31

Oxyntomodulin is released from

L cells of the lower small intestine in response to food

32

Oxyntomodulin ________ food intake and _________ energy expenditure

reduces; increases

33

Oxyntomodulin may mediate its effects via which receptor?

GLP-1 R

34

Oxyntomodulin is inactivated by

DPP4

35

T/F Oxyntomodulin is more potent than GLP-1

True

36

What is the benefit of combining PYY and oxyntomodulin?

they work synergistically to further reduce food intake

37

GIP

gastric inhibitory peptide/glucose-dependent insulinotropic polypeptide

38

What are the incretin hormones that stimulate insulin secretion?

GIP and GLP-1

39

GIP is released from

duodenal and jejunal K cells after ingestion of nutrients

40

What is the action of GIP?

stimulates insulin release, activates lipoprotein lipase (clears fat from plasma for storage)

41

What are the actions of GLP-1?

increases period of postprandial satiety, slows gastric emptying

42

GLP-1 decreases intake of

food quantity, calories, and fluid

43

Liraglutide

human GLP-1 w/attached FA molecule (enters brain more readily)

44

What is the concern with using liraglutide?

it increases HR; BP drops with weight loss but the HR does not change

45

Uroguanylin is produced in

the distal gut

46

What are the actions of uroguanylin?

decreases food intake via the brain; decreases intestinal fluid absorption via the gut

47

What happens to leptin following weight loss?

leptin decreases dramatically with weight loss (70% below fasting) and starts to rise only in proportion to weight gain

48

What happens to ghrelin following weight loss?

ghrelin increases (it still follows diurnal variation with meals) tf more hungry

49

What happens to PYY following weight loss?

PYY decreases; making you more hungry

50

What happens to CCK following weight loss?

CCK decreases; making you more hungry

51

Why do hunger hormones increase and satiety hormones decrease following weight loss?

Defensive mechanism to maintain body weight

52

T/F Hunger hormones and satiety hormones go back to baseline 1yr after weight loss

False; Ghrelin is still increased, PYY and CCK are still decreased - this is why it is so hard to maintain weight loss

53

T/F Gut hormones play an important role in the defense of body weight

True; levels of hunger hormones (ghrelin) are increased and satiety hormones (CCK, PYY) are decreased even 1yr post weight loss

54

How do gut bacteria influence body weight?

processing of dietary indegestable polysaccharides to short-chain fatty acids (butyrate, acetoacetate) which protect against bowel cancer - this increases calories and fat absorption in the liver; increased activity of LPL and tf fat storage