5 - Introduction to diabetes mellitus Flashcards
How does insulin affect HGO and muscle glucose uptake?
Decreases HGO (hepatic glucose output)
Increases muscle glucose uptake
How does insulin affect proteolysis?
Decreases proteolysis (stops the breakdown of proteins)
How does insulin affect lipids (lipolysis and ketogenesis)?
Decreases both (Ketogenesis is the breakdown of fatty acids and ketogenic amino acids to make ketone bodies)
What are 5 other things insulin is related to?
- Lipoproteins
- Smooth muscle hypertrophy
- Ovarian function
- Clotting
- Energy expenditure
What transporter does glucose enter a cell through?
GLUT4 - insulin increases the amount of these transporters to increase glucose uptake.
Hydrophilic core and hydrophobic edge.
Where is GLUT4 found?
Muscle and adipose tissue
In a muscle cell, how does insulin affect proteins?
Stops proteolysis (stops the breakdown of proteins)
Increases protein synthesis (also increased by growth hormone)
What increases proteolysis in muscle cells and what are the amino acids used for?
Cortisol
Used to make O2 into CO2
Used to make gluconeogenic amino acids.
What is the difference between where glucose and glycogen are stored?
Glucose is always present in the blood
Glycogen is stored in the liver
What happens to gluconeogenic amino acids that enter the liver?
- Used to make proteins
- Used to make new glucose (gluconeogenesis) to increase HGO
In the blood vessels and in adipose tissues, insulin has different effects on the formation and breakdown of triglycerides. Explain this.
In blood vessels, insulin encourages the breakdown of triglycerides.
Its broken down into non-esterified fatty acids and glycerol which can enter adipose tissue.
In adipose tissue, insulin encourages the formation of triglycerides. This can be from NEFAs and glycerol-3-p.
What 3 things encourage the breakdown of triglycerides in adipose cells into NEFAs?
Cats
Cort
GH
What is the omental or hepatic portal circulation?
Blood goes to the gut, picks up nutrients.
This blood goes to the liver so food can be processed BEFORE re-entering general circulation.
Adipocytes in central circulation are different to those in arms and legs. Omental adipocytes predict heart disease.
How is glycerol used to make glucose in the liver? Draw diagram
Triangle.
Glycerol enters and is made into Glycerol-3-p.
This can be made (reversibly) into triglycerides.
Glycerol-3-p makes glucose via gluconeogenesis. This is released from the liver.
What CANNOT be used to make glucose
Non-esterified fatty acids
What can the brain use as an energy source?
Glucose Ketone bodies
What can the brain NOT use as an energy source?
Fatty acids (but muscle can)
How are ketone bodies produced?
- Non esterified fatty acids enter the liver
- They are broken down into 2 carbon sections (acetyl CoA, acetoacetate, acetone + 3 OH-B)
- Make ketone bodies which are released from liver and go to brain during fasting.
Why and how are ketone bodies measured?
Ketones measured in blood or urine.
If present = patient has low insulin
Ketones in presence of high glucose = Person is insulin deficient
Draw a picture showing hepatic glycogenolysis in the liver.
Triangle.
Glucose enters liver
Made into glucose-6-p
With insulin - glucose-6-p made into glycogen.
With catacolanimes and glucagon - glycogen made back into glucose-6-p, which is made into glucose and released from liver.
What happens once glucose enters muscle cells?
It can be stored as glycogen but this cannot then be released as glucose.
It MUST be used within the muscle cell itself - enters krebs cycle.
What happens to the body in a FASTED state?
- Low [Insulin]
- High proteolysis and lipolysis
- High HGO from glycogen and gluconeogenesis.
Low insulin:glucagon ratio High NEFA Muscles use lipids Brain uses glucose then ketones Ketogenesis increases.
What happens to the body in the FED state?
Stored insulin is released.
High inulin:glucagon ratio
HGO stops More glucose stored as glycogen Gluconeogenesis stops Protein synthesis increases Lipogenesis increases
What is type 1 diabetes?
Absolute insulin deficiency - no insulin produced by pancreas.
