Module 5 Flashcards
(39 cards)
Incretin Secretion is stimulated by:
a) Spike in insulin levels
b) TAG breakdown
c) Reabsorption
d) Food intake
e) none of the above
d) Food intake;
Regulation of incretin secretion (topic)
Q: Polarized cells that sense the contents of the intestinal lumen called?
a) K cells
b) L cells
c) GIP
d) Enteroendocrine cells
e) Epithelial cells
f) Enterocytes
d) enteroendocrine cells
____ is released from K cells and ____ is released from L cells in response to nutrients in the intestinal lumen
GIP
GLP-1
True or False:
Pro-GIP is processed using PC1 to make its active form which is stored in vesicles
FALSE: it is processed by PC2
True or False:
Pro-GLP-1 is processed using PC1 to make its active form, which is stored in vesicles
TRUE
Which has a higher peak (and generally higher basal) in blood levels? and what are the values as a bonus
a) GLP-1
b) GIP
c) depends
d) both are equal
b) GIP
Basal= 10 pmol/L
Peak = 150-300 pmol/L
How were incretins discovered? What was observed in this study?
- intestinal extracts from a pig were administered to patients 3x a day
- improvements in glucose homeostasis
What is an incretin?
peptide hormones secreted from the gut
True or False:
The incretin effect says that an oral glucose load produces a REDUCED response compared to an isoglycemic IV glucose infusion.
FALSE- it produces an INCREASED response
- If someone had an impaired insulin response and needed considerable improvement, what would you do?
a) administer glucose via oral intake
b) administer via an isoglycemic IV glucose infusion - What if it was imperative (life or death) that they were able to clear the glucose from their blood after ~ 1 hour?
a) administer glucose via oral intake
b) administer via an isoglycemic IV glucose infusion
THE INCRETIN EFFECT:
1. a) oral glucose
2. still oral, IV takes a while to clear from the blood
Explain the study on the Incretin effect in mice that was completed and what it showed.
- oral glucose = **insulin spike; helps reduce bl glucose levels more effectively
- compared mice fed a normal diet vs mice fed a high-fat diet, measured both of their blood glucose and insulin levels
** no spike in insulin levels
** GLUCOSE: - 1 hour- oral vs IV were same levels ish
- CHANGE occurred in 2nd hour when they saw bl glucose from IV was higher
** this showed that IV administered glucose is not cleared as effectively from the blood.
Carbs (glucose) are potent stimulators of incretins through 2 mechanisms:
- SGLT-1; acts on transporter substrates
- Sweet taste receptors (Tas1R2, Tas1R3); act on Gs-coupled receptors
both of these mechanisms;
- lead to cell depolarization
- inc Ca2+ levels
- cause incretin-containing vesicles to release contents into circulation
True or False: SGLT-1 is necessary for lipid-dependent incretin secretion
FALSE: it is necessary for GLUCOSE dependent.
Following meal consumption, incretin response is rapid and persists for several _____; incretins are activated by ____
a) mins, DPP-4
b) secs, DPP-2
c) hours, DPP-4
d) days, DPP-2
c) hours, DPP-4
Is the half-life of GLP-1 or GIP longer?
GIP; it is 7 mins
True or False:
water intake increases active levels of GLP-1
False; water intake has no effect on incretin secretion
Obesity has _____ on GIP secretion and _____ on GLP-1 secretion
a) no effect on both
b) positive effect; negative effect
c) negative effect; no effect
d) no effect; negative effect
e) no effect; positive effect
f) positive effect; no effect
g) negative effect; positive effect
d) no effect; neg effect
In general, what effect does obesity have on active incretin levels in circulation?
a) no effect
b) negative effect
c) positive effect
b) negative effect, causes a general reduction
T/F; consumption of different macronutrients increases total and active levels of both GIP and GLP-1 in the blood.
TRUE
In the pancreas, incretins combine with ____ to _____ insulin release into the blood
glucose; increase
Correct sequence of the role of incretins in the pancreas:
a) binds to specific receptors→ formation of cAMP → decreases Ca2+ intracellular levels (hyperpol) → exocytosis of insulin granules → insulin release into blood
b) binds to specific receptors→ formation of cAMP → increases Ca2+ intracellular levels (depol) → exocytosis of insulin granules → insulin release into blood
c)binds to specific receptors→ formation of cAMP → increases Ca2+ intracellular levels (depol) → endocytosis of insulin granules → insulin release into blood
d) binds to specific receptors → increases Ca2+ intracellular levels (depol) → exocytosis of insulin granules → insulin release into blood
e) binds to specific receptors→ formation of cAMP → exocytosis of insulin granules → inc Ca2+ intracellular levels (depol) → insulin release into blood
e) binds to specific receptors→ formation of cAMP → exocytosis of insulin granules → inc Ca2+ intracellular levels (depol) → insulin release into blood
Incretins decrease:
a) appetite
b) insulin secretion
c) insulin sensitivity
d) cardiac output
e) gastric emptying
f) glucose production
SELECT ALL THAT APPLY
aef
- appetite, gastric emptying, glucose production
Incretins Increase:
a) b cell apoptosis
b) glucagon secretion
c) insulin biosynthesis
d) insulin sensitivity
e) cardiac output
f) glucose production
ALL THAT APPLY
c,d,e
- insulin biosynthesis, insulin sensitivity, cardiac output
Obesity & T2D cause _____ in incretin response
a) increase
b) decrease
c) no effect
b) decrease
