Glucagon

Question 1

Glucagon is secreted from what type of cells

Answer 1

alpha cells of pancreas

Question 2

glucagon is secreted in response to ? Primary function?

Answer 2

• glucose deficiency; amino acids in blood
• acts to increase circulating glucose levels

Question 3

primary target of glucagon is

Answer 3

the liver

Question 4

glucagon stimulates conversion of amino acids to

Answer 4

• glucose

Question 5

glucagon stimulats the release of what three things

Answer 5

• glucose
• free fatty acids
• ketoacids
• **these in turn suppress glucagon release

Question 6

what function does glucagon have on liver in terms of glucose

Answer 6

• promotes gluconeogenesis
• promotes glycogen breakdown and inhibits glycogen synthesis

Question 7

what function does glucagon have on liver in terms of keytone bodies

Answer 7

• glucagon promotes fatty acid oxidation
• excessive oxidation leads to formation of keyton bodies
  
  • can be used by the brain as fuel in fasting state

Question 8

glucagon has what effect on adipose tissue and skeletal muscle

Answer 8

increases release of fatty acids (only at high concentration of glucagon)

Question 9

Proglucagon is converted to what in the intestinal tract

Answer 9

Glucagon-like peptide-1

Question 10

function of Glucagon-like peptide-1

Answer 10

increases insulin secretion in response to a carbohydrate or protein meal : the incretin effect

Question 11

islet alpha cells of pancreas are inhibited by

Answer 11

• parasympathetic activity
• insulin

Question 12

summary of glucagon effects

Answer 12

1. glycogenolysis (hepatic glucose production)
2. gluconeogenesis
3. ketogeneisis
4. lipolysis (adipose tissue)

• **increase in plasma glucose, FFA, ketoacids, and decrease in plasma amino acids

Question 13

List sites where Somatostatin is produced

Answer 13

• pancreatic delta cells
• hypothalamus
• GI tract

Question 14

list actions of Somatostatin

Answer 14

• may inhibit or modulate response of insulin and glucagon secretion
• inhibits GH secretion

Question 15

function of cortisol on glucose

Answer 15

increased cortisol = increased blood glucose by gluconeogenesis

Question 16

Effect of growth hormone on carbohydrate metabolism

Answer 16

• decreases glucose uptake and use by muscle, liver, and adipocyte
• increases liver glucose output by gluconeogenesis
  
  • NET EFFECT -> increase in glucose

Question 17

Function of epinephrine on carb metabolism

Answer 17

• mobilizes fuel in times of STRESS
  
  • ​increased glycogenolysus
  • inhibition of glycogen synthesis
  • increased gluconeogenesis

Question 18

Which condition is associated with increased plasma growth hormone levels: abundance of food or scarcity of food?

Answer 18

both conditions are associated with increased plasma GH levels

• ex: overnight fast: low blood glucose
  
  • GH stimulates liver glucose production to compensate

Question 19

fasting state causes release of what hormones

Answer 19

• glucagon
• cortisol
• epinephrine
• growth hormone

stimulates liver glucose production to compensate

Question 20

fasting state causes inhibition of release of what hormones

Answer 20

• insulin-like growth factor
• insulin
• thyroid hormones

Question 21

why does the body not go into hypoglycemia after a protein meal

Answer 21

• insulin secretion is increased which could inhibit liver glucose production -> hypoglycemia
• BUT glucagon secreted in response to amino acids in protein balances the action of insulin

Question 22

what hormones are secreted after high protein intake

Answer 22

• glucagon
• insulin
• growth hormone
• insulin-like growth factor
• **get protein synthesis and growth and no change in caloric storage

Question 23

what hormones are secreted with ingestion of large carbohydrate meal

Answer 23

• insulin secretion increased to store glucose load
• increase in incretin: to augment insulin response
• glucagon and IGF-1 secretion suppressed due to lack of amino acids
• **increase in caloric storage; no change in protein synthesis or growth

Question 24

brain utilizes what percentage of glucose during exercise

Answer 24

20%

Question 25

can skeletal muscle secrete glucose?

Answer 25

no

Question 26

during exercise, a balance must be made between glucose uptake by and release by

Answer 26

1. skeletal muscle 2. liver

Question 27

elevation of _what hormones_ during exercise promotes the use of as fuel

Answer 27

* hormones * GH * epi * NE * FFA

Question 28

within the first 6 minutes of exercise, most energy is derived from

Answer 28

glycogen and glucose

Question 29

after 10 minutes of exercise, most energy is derived from

Answer 29

FFA

Question 30

The myokine IL-6 increases during exercise. what is its function

Answer 30

* increases glucose uptake and fat oxidation in skeletal muscle * may also increase hepatic glucose production and lipolysis of adipose tissue

Question 31

what happens to insulin secretion during exercise?

Answer 31

insulin secretion is suppressed during exercise by catecholamines

Question 32

since insulin secretion is inhibited in exercise, how does glucose get into skeletal muscle

Answer 32

glucose uptake into skeletal muscle is facilitated by **contraction medatiated** mechanisms using **GLUT-4**

Question 33

why does plasma glucose spike in response to an intense acute exercise

Answer 33

* increased release of catecholamines stimulates liver release of glucose * working muscles utilizes stored glucose first during intense exercise

Question 34

training has what effect on plasma glucose throughout exercise

Answer 34

plasma glucose remains higher and more stable than untrained individual

Question 35

training has what effect on plasma glucagon throughout exercise

Answer 35

trained individual has a lower plasma glucagon throughout exercise

Question 36

training has what effect on plasma insulin throughout exercise

Answer 36

plasma insulin remains lower in trained individual