Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Endocrinology & Reproduction > Incretin hormones > Flashcards

Incretin hormones Flashcards

1
Q

what is the incretin effect

A

there is an enhanced insulin secretion in response to oral glucose compared to IV glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are incretins

A

small peptide hormones released from the GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

when are incretins released

A

in response to food intake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what does incretin release do

A

enhance the effect of insulin secretion in reponse to glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

where re incretins released from

A

GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

two main incretins

A 
GIP = glucose-dependent insulinotropic polypeptide
GLP-1 = glucagon-like peptide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is GIP

A

glucose-dependent insulinotropic polypeptide

42 AA peptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is GIP synthesised from and where

A

proGIP from K cells in the proximal GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is the proximal GI tract

A

upper part; duodenum and proximal jejunum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where does GIP go

A

from GI tract to islet cells, carried in the circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is GLP-1

A

glucagon-like peptide

30 AA peptide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

what is GLP1 synthesised from and where

A

proglucagon in the L cells in the distall GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is the distal GI tract

A

Colon & ileum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

where are K cells

A

proximal GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

where are L cells

A

distal GI tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what do K cells produce

A

GIP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what do L cells produce

A

GLP-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is proglucagon a precursor of

A

in alpha cells = glucagon

in L cells = GLP-1, glicentin & GLP-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

5 beneficial effects of GLP-1

A
  1. stimuates insulin secretion
  2. decreases glucagon secretion
  3. delays gastric emptying
  4. decreases appetite
  5. increases beta cella mass via increased proliferation and reduced apoptosis
20
Q

when is the incretin effect reduced

A

T2D

21
Q

how is the incretin effect changed in T2D

A

people with T2D will have a lower than expected insuliin respose to oral glucose. There is not a big difference seen between IV and Oral glucose as there is with the incretin effect

22
Q

What area GIP levels like in T2D compared to normal?

A

relatively the same but has reduced effect to stimuate insulin secretion

23
Q

What area GLP-1 levels like in T2D compared to normal?

A

may be decreased

24
Q

what degrades GLP 1 and GIP

A

DPP-E depeptidyl peptidase 4

25
Q

What does DPPE degrade

A

GLP1 and GIP

26
Q

what is the half life of GIP

A

~5 minutes

27
Q

why is GIP not a candidate for T2D drug therapy

A

receptors are insensitive to GIP and so will have no effect on insulin release

28
Q

why could GLP-1 work as T2DM treatment

A

although lower levels, the GLP-1 that is present does work and stimulates insulin secretion

29
Q

why wont GLP-1 work as T2DM treatment

A
  • degraded by DPP4

- half life of 2 minutes

30
Q

half life of GLP1

A

2 minutes

31
Q

how does DPP4 work

A

inactivates GLP & GIP by removing two AA from the N-terminal

32
Q

how do DPP4 inhibitors work

A

they block the clevage of the AA from the N-terminal, so GIP and GLP-1 are not inactivated

33
Q

what happens to blood glucose levels in presence of DPP4 inhibitors

A

blood glucose levels are reduced, becuase GLP-1 and GIP are able to act on islet cells to stimulate insulin secretion

34
Q

effective drug treatment of T2DM that has been used since 2006

A

DPP4 inhibitors

35
Q

how can the half life of GLP-1 be exteneded

A

DPP4 inhibitors do this

36
Q

what is exendin-4

A

A GLP-1 like peptide identified in the saliva of the Gila monster. It has an AA sequence similar enough to GLP-1 to have the same actions

37
Q

what is the benefit of exendin 4

A

it has a similar AA sequence to GLP-1 to have the same actions, but it is not a substrate for DPP-4 and so is not degrarded

38
Q

synthetic version of exendin 4

A

exenatide

39
Q

half life of exenatide

A

in vivo 2 hours

40
Q

what is exenadine

A

synthetic version of exendin 4.
39 AA with 50% homoogy with GLP-1
stimulates insulin secretion

41
Q

why can’t GLP-1 analogues be used to treat T1DM

A

islet beta cells are destroyed in T1DM and so insulin cannot be secreted

42
Q

can GLP-1 analogus be used to treat T1DM

A

No; islet beta cells are destroyed in T1DM and so insulin cannot be secreted

43
Q

what benefit do GLP-1 analogues have in T1DM

A
  • Inhibit glucagon secretion which leads to less glucose production from the liver
  • delays gastric emptying which delays peak increase in plasma glucose after food
    they are associated with weight loss in T1DM
44
Q

is weight a problem for T1DM?

A

although T1DM is a consequence of autoimmune assultt and not excess BMI, weight gain is occured with insulin,

45
Q

GLP-1 has beneficial effects on several organs. Name them

A

brain: promotoes satiety, reduces appetite
islet alpha cells: reduces glucagon secretion
liver: reduced glucagon = reduced hepatic glucose secretion
stomach: delayed gastric emptying
islet beta cells: enhanced glucose-dependent insulin secretion
fat & muscle: increased insulin = increased glucose uptake and storage

Endocrinology & Reproduction (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions