Counter regulatory hormones

Question 1

Briefly state how metabolism works during fasting

Answer 1

• Inhibition of insulin secretion
• Low glucose levels
• No glycogen or triglyceride synthesis

Question 2

Which hormones promotes the processes usually supressed by insulin in starvation

Answer 2

Glucagon

Question 3

Briefly describe the graphical relationship between glucagon and insulin

Answer 3

If glucose and insulin go up, glucagon goes down and vice versaq

Question 4

Which cells secrete glucagon

Answer 4

Alpha cells

Question 5

Describe the structure of glucagon hormone

Answer 5

Peptide hormone made up of only 1 cchain

29 amino acids

Question 6

When is glucagon secreted

Answer 6

When blood glucose levels are low

Question 7

How is glucagon stored

Answer 7

In granules

Question 8

Name 3 things that stimulate glucagon secretion

Answer 8

Low blood glucose
Increased blood amino acid
Exercise

Question 9

What are normal fasting levels of glucose

Answer 9

80-90mg/ 100ml

Question 10

Which blood amino acids particularly regulate glucagon secretion

Answer 10

Alanine and arginine

Question 11

What type of receptor in the glucagon receptor

Answer 11

G protein coupled receptor

Question 12

What is the first thing that happens when glucagon binds to the glucagon receptor

Answer 12

• G protein splits off

- Starts the cascade

Question 13

What is the end point of the cascade in glucagon receptor signalling pathway

Answer 13

Production of cAMP which activates protein kinase A
Protein kinase A activates signal
Increases breakdown of glycogen to stop glycogen synthesis

Question 14

What is the effect of PKA on the liver

Answer 14

Stimulates liver to make glucose via gluconeogenesis

Stops glycolysis

Question 15

Does glucagon increase or decrease glycogenolysis

Answer 15

Increases

Question 16

How long does it take for glycogen stores to be broken down

Answer 16

24 hours

Question 17

What molecules can the liver use for gluconeogenesis

Answer 17

Carbon based subtrates (amino acids, glycerol)

Question 18

How is gluconeogenesis not inhibited during fasting

Answer 18

Combination of reduced insulin and increased glucagon

Question 19

What is the effect of glucagon in the liver

Answer 19

Increased gluconeogenesis and inhibits glycolysis

Question 20

How does glucagon increase gluconeogenesis and inhibit glycolysis in the liver

Answer 20

• Inhibition of PFK-1 through modulation of fructose-2,6-bisphosphate levels
• Inhibition of pyruvate kinase

Question 21

What mediates the action of glucagon in the liver

Answer 21

Protein kinase A

Question 22

Does glucagon increase or decrease the uptake of amino acids into the liver

Answer 22

Increase

Question 23

What inhibits/ activates hormone sensitive lipase

Answer 23

Inhibited by insulin

Acitvated by glucagon/ PKA

Question 24

What does hormone sensitive lipase do

Answer 24

Initiate lipolysis

Question 25

How can fatty acids be used to generate ATP

Answer 25

Enters the krebs cycle

Question 26

What mediates the fatty acids shuttle system

Answer 26

Cpt-1

Question 27

Does insulin supress or promote the action of Cpt-1? What about glucagon?

Answer 27

Insulin- suppresses | Glucagon- promotes

Question 28

What is the effect of glucagons inhibition of cpt-1

Answer 28

- Allows breakdown of triglycerides to be broken down because activates hormone sensitive lipase needed to break it down - Also allows passage across mitochondria membrane

Question 29

Overall, what hormones suppress and promotes fatty acid oxidation

Answer 29

Glucagon- promotes | Insulin- suppresses

Question 30

What is acetyl- CoA converted to in prolonged fasting

Answer 30

Ketone bodies

Question 31

Name 2 hormones that inhibits glucagon secretion

Answer 31

Insulin | Somantostatin

Question 32

How is cAMP used to regulate glucagon secretion

Answer 32

Insulin converts cAMP to AMP which can't signal anymore so there is no glucagon action

Question 33

Is it catecholamines or glucocorticoids that have a long term effect

Answer 33

Glucocorticoids

Question 34

What is the effect of catecholamines

Answer 34

Stimulates glycogen breakdown from the liver1q

Question 35

When are catecholamines released

Answer 35

Response to stress of hypoglycaemia

Question 36

What are monoamines of catecholamine synthesised from

Answer 36

Phenylalanine | Tyrosine

Question 37

State the metabolic action of epineprhine

Answer 37

Inhibits insulin secretion Stimulates glycogenolysis in liver and muscle Stimulates glucagon secretion Increases lipolysis

Question 38

Consequence of epinephrine release in terms of blood levels

Answer 38

Increased blood glucose and fatty acids levels

Question 39

What kind of hormones are glucocorticoids

Answer 39

Steroid

Question 40

How are adrenal cortex cells adapted for steroid hormone production

Answer 40

Many LDL receptors enabliing cholesterol uptake for steroid hormones synthesis

Question 41

What is cortisol released in response to

Answer 41

ACTH

Question 42

State the metabolic actions of cortisol

Answer 42

- Enhances gluconeogenesis - Inhibits glucose uptake - Stimulates muscle proteolysis - Stimulates adipose tissue lipolysis

Question 43

Why does cortisol produce long term responses

Answer 43

Because is hydrophobic so can pass through the cell membrane | Binds to nuclear receptor

Question 44

What happens if levels of cortisol are high for a long time

Answer 44

induce proteolysis and muscle wasting

Question 45

Does growth hormone act more like insulin or glucagon

Answer 45

Glucagon

Question 46

Are cortisol and epinephrine secreted in hypo or hyper glycaemia

Answer 46

Hypo

Question 47

Where are incretins found in the body

Answer 47

Gastro-intestinal hormones

Question 48

Where is GLP-1 secreted

Answer 48

From the L cell

Question 49

4 actions of GLP-1

Answer 49

Inhibits glucagon secretion and hepatic glucose production Augments glucose induced insulin secretion Slow gastric emptying Promotes satiety