Glucose Regulation

Question 1

What does insulin do?

Answer 1

• major metabolic regulator
• facilitates entry of glucose into muscle, adipose, and other tissues
• increases glycogenesis (synthesis of glycogen)
• increases lipogenesis, decrease lipolysis
• decreases proteolysis (protein breakdown)
• stimulates glycolysis
• stimulates cholesterol synthesis (increases HMG-CoA reductase enzyme)
• DNA growth factors, etc.

Question 2

where is the first place to get the sugars that we consume?

Answer 2

the liver

Question 3

shortened version of glucose coming into cell and insulin being released

Answer 3

*glucose comes into cell via GLUT2 transporter
*goes through glucose metabolism, producing ATP
*increase in ATP blocks ATP sensitive potassium channel causing an increase in potassium inside the cell
*this causes depolarization and opens the voltage gated calcium channel
*calcium floods in, causing stored insulin to be released via exocytosis

this is why poor insulin release can be due to lower potassium levels (it can’t depolarize to increase calcium to release insulin*

Question 4

if someone comes in with IR (insulin resistance) what should you give them?

Answer 4

Antioxidants
- address ROS and mitochondrial dysfunction
- IR can be a cellular antioxidant defense mechanism

Question 5

where is glucagon secreted and what is this hormones primary role

Answer 5

secreted by the alpha cells in the pancreas
primary role = increase BS levels
**usually released during fasting or btwn meals to help increase and stabilize BS

Question 6

mechanism of action of glucagon

Answer 6

*liver: stimulates liver to breakdown stored glucagon (produces glucose)– increases BS
*gluconeogenesis: synthesis of new glucose (from non-carb sources- AA or glycerol– occurs primarily in the liver)
*adipose tissue: stimulates the breakdown of TG stored in adipose tissue into FFA and glycerol– glycerol released can be stored in liver for gluconeogenesis- further contributing to increase BS

Question 7

what are the insulin sensitive tissues

Answer 7

liver, muscles, adipocytes

Question 8

what are the non-insulin sensitive tissues

Answer 8

brain, blood cells, nerve, etc.

Question 9

during a fasting state, what percent of glucose going into cells DONT need insulin?

Answer 9

83%

Question 10

What is known about GLUT1?

Answer 10

found in muscle- known to only be in RBC and neurons
- can be insulin-independent
- influx of glucose, increase glucose reuptake most likely through GLUT1 receptor
*inflammation stimulates GLUT1 entry into cells, increase hexosamines- which inhibits GLUT4– when glucose increases, GLUT4 is impaired