Endocrinology 19 Flashcards
How does Insulin affect the muscle tissue?
Insulin increases the uptake of glucose by muscle tissue and increases its deposition into the glycogen storage form
How does Insulin affect Adipose tissue?
It increases the uptake of glucose into fatty or adipose tissue
What can glucose be converted to in Adipose tissue?
Fatty acids or triglycerides
How does insulin affect the transport of glucose into the liver?
It doesn’t
How does insulin influence the liver?
It stimulates or inhibits various enzymes so that more glucose can be converted to glycogen
How does insulin affect amino acids and muscle?
Insulin increases the uptake of amino acids into muscle
What can happen once amino acids enter the muscle?
They can be converted into protein
How does insulin affect amino acids and the liver?
Insulin increases the uptake of amino acids into the liver
What is the overall role of insulin?
It increases the uptake of glucose into various tissues to be converted into different storage molecules
Which tissues can take up glucose in the absence of insulin?
The liver and the brain
What is glycogenesis?
Building up glycogen
What is glycogenolysis?
Breaking down glycogen
What is gluconeogensis?
The formation of glucose from non-carbohydrate substances
What kind of hormone is insulin?
A protein hormone
What is the insulin receptor made of?
2 alpha and 2 beta subunits
What do the intracellular portion of the insulin receptor have?
Tyrosine kinase activity
How does binding of the insulin receptor to insulin affect it?
It activates the tyrosine kinase activity
What happens when tyrosine kinase becomes active due to the presence of insulin and its receptor?
It causes changes in insulin receptor substrates which can affect transport systems, enzyme activity, gene expression
What are the two families of transport mechanisms of glucose?
- SGLTs (secondary active transport)
* GLUT (facilitated transport)
Which transporters transport glucose through secondary active transport?
SGLT 1 and SGLT 2
How do SGLT 1 and SGLT 2 work?
They transport glucose by secondary active transport at the same time as sodium
Which direction does glucose move with SGLT transporters?
Uphill
Which direction does glucose move with GLUT transporters?
Downhill
Which GLUT is insulin sensetive?
GLUT 4
Where us GLUT 1 and 2 found?
In the GI tract
In which cells does insulin affect glucose transporters?
Muscle and adipose cells
How does insulin cause it effects on GLUT 4?
It causes them to dock into the cell membrane from vesicles and allow glucose in
Through what mechanism does Glucagon act?
via cAMP
Where does glucose come from short term?
Glucose is readily available in blood soon after a meal is eaten
Where does glucose come from long term?
The liver glycogen stores are broken down through glycogenolysis
What does Glucagon do?
Increases mobilization of fuels when needed
Where is the main site of action of glucagon?
The liver
How does Glucagon affect blood glucose?
It increases blood glucose
