Glucose Disposal Flashcards
Intolerant
Normal fasting glucose but a sluggish clearance
Diabetic
Fasting hyperglycemia
unable to get rid of glucose and will often start with high BG
What is secreted when glucose levels are low? Where?
Glucagon at alpha cells
What is secreted when glucose is high? Where
Insulin at beta cells (Islet of Langerhans)
Insulin Resistant
need to secrete more insulin in order to get rid of the glucose
What is insulin intolerant?
Secreting more insulin but not enough to get over resistance. Thus can’t respond to the high levels of BG, so secreting high level of insulin
Hyperinsulinemia
What is Types 2 Diabetes?
Beta-exhuasted
- not able to secrete much insulin, thus not able to respond to the glucose
- not able to maintain basal levels
Two forms of Starch:
- Amylose
- Amylopectin
Amylose
- linear, forms helices
- difficult for amylases to penetrate
- flatulence
Amylopectin
- Branched
- easy digestion/ hydrolysis (Easy for amalyase to breakdown)
The glycemic index
describes the post-prandial glucose response
Removal of glucose from bloodstream in liver - what transporter?
GLUT2
- insulin independent
Removal of glucose from bloodstream- in muscle?
GLUT4
- insulin dependent
- has a high capacity of getting rid of glucose
What is the purpose of adding a phosphate to glucose?
What phosphate group?
To trap the glucose inside the cell, thus is now charged and can’t move across.
Hexokinase
Glycogen synthesis is regulated by what?
Reverse phosphorlyation
When dephosphorylation occurs, is it active or inactive?
Active
Glucose stimulates it
What catalysed dephosphorylation?
Phosphates (PP1)
When phosphorlyation occurs, is it active or inactive?
Inactive
What catalyses phosphorylation?
Kinases
What does insulin stimulate?
Insulin stimulates PPI, which causes GS to be active and dephosphorylate.
What stimulates phosphofructokinase (PFK)?
AMP, low energy charge/ level (of ADP)
How can insulin cause an increase in glycolysis?
Glycogenesis is anabolic (thus requiring ATP). As a result ATP levels drop and ADP levels increase.
This drop in energy charge stimulates PFK, which sitmulates catabolic pathway - oxidation of glucose
What are levels of blood glucose and liver glucose
they are the same
Purpose of glucokinase
Converts G –>G6P
Relationship between G6P and blood glucose
As G6P increases so blood glucose rises
What can G6P stimulate?
can stimulate inactive GS and phosphorylate GS
Push mechanism - liver
Glycogenesis will respond to BG without insulin
- However insulin will stimualte glycogen synthase further
Muscle
[G6P] never gets high enough to stimulate GS
- insulin dependent
Glucokinase
- Where it works?
- present ?
- purpose
- only works on glucose (high levels of glucose)
- not inhibited by G6P
- only present in liver, beta cells
- responsive to changes in glucose blood
Hexokinase
- works on any sugar 6C
- low levels of glucose
- inhibited by G6P- if there are too many G6P not used, then will build up and inhibit hexokinase
- easily saturated with glucose
- present in all other tissues
What is required for the incorporation of glucose into glycogen chain
ATP
G–> G6P, UDP –> UTP
