Insulin and Glucagon Flashcards
What are the two sources that blood provides fuel from?
–dietary fuels from carb, fat, protein directly from the gut
–stored fuels from glucose, fatty acids, amino acids
Red blood cells rely on what to make ATP?
glucose
Most tissues in the body are ______ when it comes to reliance on substances to make ATP.
versatile
Tissues that are don’t absolutely require glucose can switch to what for ATP? Why?
fatty acids
to allow tissues that require glucose to get the remaining gluose
The brain relies on what to make ATP?
mainly glucose but in times of starving ketone bodies
The master controllers of fuel storage, metabolism and switching are:
insulin
glucagon/catecholamines
Insulin and glucagon/ catecholamine levels in the blood are regulated by:
blood glucose concentrations
Glucagon and stress hormones sends what where?
mobilized stored fuels to be used (glucose, fatty acids and amino acids)
Insulin/glucose inhibits _______
glucagon release
After eating insulin sends what, where?
fuel, to be stored
Actual duration of post-prandial
glucose/insulin pulse depends
on:
how fast carbohydrate is
absorbed from the gut
What happens to blood fuel levels after a high protein, no carbohydrate meal?
- small increase in insulin stimulates a.a. uptake and protein synthesis
- large increase in glucagon controls glucose and fatty acid metabolism
(glucagon has no effect on a.a. uptake or protein synthesis) - balance of insulin and glucagon keeps glucose levels steady
What is the difference between epinephrine and cortisol effects on fuel?
ep is more immediate
cortisol is long term
what regulates the release of insulin?
Major: high glucose level
low: amino acids, neural input, gut hormones
what regulates the release of glucagon?
low glucose/insulin
amino acids
(insulin is the most major effector of glucagon levels)
Why does insulin level slightly rise even after a no carb meal?
When the amino acids are being used to make ATP that increase in ATP stimulates the slight release of insulin
What effect does insulin have on the liver?
metabolic and enzymatic changes but not change of entry of glucose to the liver
Insulin has no direct effect on
glucose transporters in liver cells
Insulin and glucagon are
–both are ________ sustained action depends on continuous secretion
– both act at the ________ of their target cells
–both are short-lived in the blood (minutes)
sustained action depends on continuous secretion
- both act at the cell surface of their target cells
-do not enter the target cell (2nd messenger systems)
What are examples of insulin sensitive tissues?
muscle, adipose tissue
What effect does glycogen have on muscle tissue
none, the muscle does not have a receptor for glucagon
what tissues are sensitive to glucagon?
liver and adiposities
insulin and glucagon are what type of hormone?
polypeptide
Protein phosphatases ______ ______ from phosphorylated amino acids
hydrolyze phosphate
The insulin receptor becomes a ____ _____ _____when it is activated by insulin
protein tyrosine kinase
Protein kinases use ATP to ______ amino acids on substrate proteins
phosphorylate
when are g protein active?
when GTP is bound
(inactive when GDP is bound)
how does glucagon effect messages across cell membrane?
2nd messenger
From the point of view of fuel metabolism, the most important
effect of insulin is ________
activation of protein phosphatase-1 and AKT
Because the insulin signal transduction also activates protein phosphatase 1, a significant effect is to
________ enzymes that are substrates for protein kinase A
dephosphorylate
