Introduction to Diabetes Mellitus Flashcards
What is the action of insulin?
- Glucose
- decrease HGO
- increase muscle uptake
- decrease proteolysis
- decrease lipolysis
- decrease ketogenesis
What are the clinical implications of insulin?
- Type 1 diabetes mellitus
- Hypoglycaemia
- Insulin Resistance
- Type 2 diabetes mellitus
- Management
What is Glut-4?
- Common in myocytes (muscle) and adipocytes (fat)
- Highly insulin-responsive
- Lies in vesicles
- Recruited and enhanced by insulin
- 7-fold increase glucose uptake
How does insulin effect cell metabolism in fed state?
- In fed state, insulin inhibits the breakdown of protein in the muscle and reduce oxidation of amino acids
- Converts amino acids to proteins
How does insulin effect cell metabolism in fasting state?
- Cortisol can increase breakdown of protein which can release Amino acids out of muscle (these are called gluconeogenic amino acids AAs e.g. alanine)
- GH stimulates protein synthesis
What happens in gluconeogensis in the liver?
- Gluconeogenic AAs and pyruvate and lactate are taken up by the liver with glucagon
- In fed state insulin increase protein synthesis
- In fed state Insulin inhibits gluconeogensis
What is your fuel source from?
- Carbohydrate (most from)
- Protein (20%)
- Fat (30-40%)
What does lipoprotein lipase (LPL) enzyme do?
Breaks down triglycerides that would otherwise be unable to leave the circulation
What happens to triglycerides in the blood stream?
- Triglycerides broken down by LPL which needs insulin
- Therefore the triglycerides is broken down in glycerol and NEFAs and these are taken up by fat cell (adipocyte)
- If really eaten then glucose can also be take up by the adipocyte so in fed state insulin increase glucose uptake into the fat cell and the insulin converts the glycerol and NEFA into triglycerides to store it
- In fed state insulin inhibits breakdown of triglycerides in fat cell
- In fasting cell GH and cortisol help to break down triglycerides to form NEFA and glcycerol in the fat cell which are related from fat cell to use as a fuel source
What is the hepatic portal circulation?
- Blood from the heart to the gastrointestinal system where take to liver to be processed/stored
- Insulin from pancreas related into hepatic portals circulation so quick response
What happens to glycerol in the liver?
- Glycerol into liver by transporter to form Gly-3P then stored as triglycerides or converted into glucose by gluconeogensis
- This glucose then released as hepatic glucose
How much is hepatic gluconeogensis occur?
25% HGO after 10 hour fast
What can the brain use as fuel?
- Glucose (its no1)
- Ketone bodies
- NOT fatty acids (NEFA)
What happens to NEFA in liver?
- NEFA in liver taken up
- Converted to fatty acid CoA
- In fed state, insulin will inhibit acetyl CoA into ketone bodies but glucagon stimulates it
- Abnormal when high glucose and still have high ketone bddies
What is hepatic glycogenolysis?
-The generation of glucose from stored glycogen in the liver
What happens to glucose in the liver?
- Glucose enter liver by transporter and converted to Glucose 6 phosphate
- Insulin stimulates it to convert it to glycogen
- Glucagon stimulates formation of glucose 6 phosphate form glycogen
- Glucose then related from liver and this is NOT new glucose just stored glucose as glycogen