Introduction to Diabetes Mellitus Flashcards
What effects does insulin have on glucose?
Decrease hepatic glucose output. Increase uptake of glucose by muscles.
Describe insulins effects on protein metabolism
Decreased proteolysis
How does insulin effect lipid metabolism
Decrease lipolysis Decrease ketogenesis Ketone bodies are an energy source instead of glucose when we have not eaten. The brain can even use glucose. If we eat a meal there is no need to make ketones. If someone has ketones in their urine, they are difficient insulin. After we had a meal there is no need to make ketones.
List the other effects (mitagenic) of insulin
Lipoproteins Smooth muscle hypertrophy especially in arteries. Ovarian Function Clotting
In what tissues is GLUT 4 very abundant in?
GLUT-4 is particularly abundant in muscle and adipose tissue. NOT LIVER
What stimulates GLUT 4 to move from vesicle to the plasma membrane?
Insulin GLUT-4 is insulin responsive
What is the structure of a GLUT-4 receptor.
It has hydrophobic elements on the outside embedded in the membrane and a hydrophilic core which allows glucose into the cell - it is insulin responsive .
GLUT-4 sits in vesicles within the cytoplasm - insulin recruits them to the membrane thus causing up to 7-fold increase in glucose uptake.
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By how much does GLUT-4 increase glucose uptake?
7x
List all of the effects of insulin on protiein?
This is a muscle cell .
Insulin stops proteolysis.
Cortisol increases proteolysis when we’re stressed.
Amino acids could be oxidised in the muscle cell and insulin prevents oxidation of amino acids.
Insulin increases the re-synthesis of proteins from amino acids -Protein synthesis.
The amino acids could get in to the circulation and move to the liver where it can be used to produce glucose- these are the gluconeogenic amino acids. add pic
Name something that stimulates protein synthesis in the liver?
Insulin
List the effects of insulin on the liver
This is the LIVER.
Gluconeogenic amino acids enter the liver via specific transporter channels.
Glucagon increases the uptake of amino acids by the liver.
In the liver, protein synthesis is stimulated by insulin.
The amino acids can, however, be used to make glucose - GLUCONEOGENESIS.
Insulin inhibits gluconeogenesis.
Somatotrophin, Cortisol, Catecholamines and Glucagon increase gluconeogenesis.
The glucose produced from gluconeogenesis can then enter the circulation as HEPATIC GLUCOSE OUTPUT (HGO).
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So insulin has TWO effects on fat depending on where it acts: List these effects.
Blood - breaks down the fats so that it can enter the adipocyte Adipocyte - promotes formation of triglyceride and storage of fat and inhibits lipolysis
List the effects of Insulin on Adipocytes
Here we have an adipocyte and a blood vessel next to it .
Triglycerides come in the vasculature and are too big to enter the adipocyte directly .
Triglycerides have to be broken down by LIPOPROTEIN LIPASE before it can enter the adipocyte.
Lipoprotein Lipase is stimulated by insulin.
Triglyceride is broken down into glycerol and non-esterified fatty acids which are absorbed into the adipocyte.
Glucose also enters the adipocyte and can be used to make NEFA -non-esterified fatty acids.
Glucose can also be chopped up to make two glycerols and the fatty acids can be stuck to the glycerol to make triglycerides .
Insulin will stop lipolysis and the four counter-regulatory hormones will promote lipolysis.
So insulin has TWO effects on fat depending on where it acts:
Blood - breaks down the fats so that it can enter the adipocyte
Adipocyte - promotes formation of triglyceride and storage of fat and inhibits lipolysis. add pic
What is a simple indicator of ischeamic heart disease?
So, omental fat/waist circumference is a simple indicator of an individual’s risk of ischaemic heart disease
Where does glycerol from food and adipocytes enter to?
Liver
What is glycerol used to make in the liver?
Triglycerides or glucose. Glycerol could also be used to make glucose - form of gluconeogenesis . Two glycerols can, in effect, be stuck together to make glucose - this supports HEPATIC GLUCOSE OUTPUT.
After a fast of 10 hours, what percentage of our hepatic glucose output is supported by new glucose production.
After a fast of 10 hours, 25% of our hepatic glucose output is supported by new glucose production
Describe the diagram below of the use of glycerol by the liver. add pic.
Glycerol coming from adipocytes and food enters the liver.
This glycerol is used to make Triglycerides.
The triglycerides can then enter lipoprotein particles.
Glycerol could also be used to make glucose - form of gluconeogenesis .
Two glycerols can, in effect, be stuck together to make glucose - this supports HEPATIC GLUCOSE OUTPUT.
Glycerol can be used to make glucose but fat CANNOT re-enter the glucose pathway.
After a fast of 10 hours, 25% of our hepatic glucose output is supported by new glucose production.
List the fuels the brain can use?
Glucose Ketone Bodies BRAIN CANNOT USE FATTY ACIDS- it wouldnt be a good idea for brain tissue to break down fat.
How does insulin effect Ketone Body Synthesis in the Liver
Fatty acids generated from lipolysis can enter the liver and be used to make ketone bodies.
Insulin INHIBITS the conversion of Fatty Acyl CoA to Ketone Bodies .
Glucagon PROMOTES the conversion of Fatty Acyl CoA to Ketone Bodies.
Ketone bodies will enter the circulation and mainly be used by the muscles.
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