Post Prandial Glucose Metab Flashcards
(15 cards)
1
Q
Exocrine pancreas portion
A
98-99%
2
Q
Endocrine pancreas portion
A
1-2%
3
Q
Islets of Langerhans
A
50-300 cells
- alpha, beta, delta and theca cells
- core is made up of B cells
4
Q
B cells
A
- insulin and amylin
5
Q
a cells
A
glucagon
6
Q
Delta cells
A
somatostatin
7
Q
theca cells
A
pancreatic polypeptide (PP)
8
Q
Insulin synthesis
A
- made as a preprohormone.
- requires 2 enzymes to make it ‘insulin’
- PC= prohormone convertase
- PC2–> makes the prohormone
- PC1–> makes the hormone
- insulin is a 2 chain peptide
9
Q
Is insulin packaged into vesicles? What else is there?
A
- packaged into secretory vesicles
- these vesicles also contain endopeptidases
10
Q
How many phases of insulin secretion? What are they?
A
- secreted in response to nutrient stimuli in 2 distinct phases
1) Sharp rise in secretion, 2-5 mins
2) If glucose is still high, then prolonged secretion phase kicks in. Lasts as long as stimulus.
11
Q
Insulin release
A
- in response to glucose, aas and FAs
12
Q
Incretins
A
- Gut derived hormones
- secreted in response to nutrients
- 2 main hormones:
1) GLP1
2) GIP
13
Q
GLP1
A
- most potent incretin
- secreted form L- cells in SI
- released in response to glucose and FAs
- binds to R on B cells
- stimulates PROINSULIN synthesis
- Other actions:
a) Inhibits glucagon secretion
b) stimulates insulin synthesis
c) Promotes B cell differentiation, proliferation and maturation
14
Q
GLP1 as a therapeutic
A
- has a very short 1/2 life
- Rapidly broken down by DPPIV
- E.g. Exenatide
- -> this is a GLP1 R agonist (so mimic the incretin)
15
Q
Amylin
A
- co-stored and co-released with insulin from B cells
- inhibits glucagon secretion
- delays gastric emptying
- inhibits food intake
- deficient in T1DM
