1a Diabetes Mellitus Flashcards
Describe the normal response to feeding?
- Eat a meal
- Glucose levels in the blood are elevated
- Pancreas releases insulin
- Insulin binds to insulin receptor
- This causes GLUT4 receptors to move to the plasma membrane of the cells
- Therefore glucose is able to pass into the muscle or fat cell
Where are GLUT 4 receptors found?
muscle or adipose tissue
How does GLUT 4 respond to insulin?
It is highly insulin responsive
Where is GLUT 4 found before moving to the cell membrane?
Found in vesicles -moves from vesicles to membrane in the presence of insulin
What does insulin act as a signal of?
Insulin is a signal you have been fed
What happens to gluconeogenesis when insulin levels are high?
Gluconeogenesis is turned off
What happens to glycogen levels when insulin is released?
Glycogen levels increase as the glucose is stored as glycogen
Why is triglycerides the most useful energy store?
It is fully reduced therefore is the mot efficient energy store
What are NEFAs?
Non-esterified fatty acids
How do triglycerides form?
They form through an esterification reaction of three NEFA’s and a glycerol molecule
What is the purpose of adipocytes?
To store energy
What does lipoprotein lipase do?
Breaks down triglycerides => glycerol and NEFA molecule
What affect does insulin have on lipoprotein lipase?
Insulin switches on lipoprotein lipase
What happens to the glycerol in adipose cells from the breakdown of the triglyceride?
Can be converted into glucose - via gluceoneogenesis by conversion into dihydroxyacetone phosphate and then into GALP
What is increased due to the effects of insulin in the fed state? - 3
INCREASED:
- Glycogen store
- Lipogenesis
- protein synthesis
What is the brains main energy substrate?
Glucose
Can the brain use ketone bodies or fatty acids as a source of energy?
Can use ketone bodies as a last resort, but not fatty acids
Why can fatty acids not be used in the brain as a source of fuel?
The fatty acids cannot pass the blood brain barrier
What happens to insulin levels during starvation?
They fall
What happens to glucose uptake in cells during starvation?
It falls
What happens to hepatic glucose output?
it rises
What happens to lipolysis when insulin levels are low?
Lipolysis is switched on
What happens in lipolysis?
Non esterified fatty acids are released
What happens to the NEFA’s that are released during lipolysis?
They are converted into ketones
What happens to blood pH when ketones are made and why?
Blood pH starts to fall - this is because ketones are slightly acidic
What happens to gluconeogenesis when insulin levels are low?
The liver turns on gluconeogenesis
What is hepatic glycogenolysis?
The generation of glucose from stored glycogen in the liver
What effect does low insulin levels have on beta oxidation?
Increases beta oxidation
What is produced in beta oxidation?
acetyl coa which is then used to produce ketone bodies in the starving state
What are the three ketone bodies?
Acetone
Acetoacetate
3-beta hydroxybutyrate
Starving for a long period of time results in a sweet, strong smell that you can detect. Why?
Starving state = increased gluconeogenesis, meaning the oxaloacetate which would normally be used in the TCA cycle is being used to make glucose, therefore excess of acetyl CoA - converted into ketone bodies via ketogenesis
What happens in myocytes when insulin levels are low?
no glucose is pumped into muscle cells, so the onboard stores of glycogen are used to make glucose, which then undergoes glycolysis and Krebs cycle to make ATP
What happens to proteolysis when insulin levels are low?
It increases - proteins are broken down into amino acids
What happens to hepativ glucose output when inculin levels are low
It increases
What happens to ketogenesis when insulin levels are low?
It increases
What type of disease is Diabetes Mellitus?
An autoimmune condition