Pancreatic Hormones

Question 1

How many amino acids are in the A chain

Answer 1

21 amino acids

Question 2

How many amino acids are in the B chain

Answer 2

30 amino acids

Question 3

How many amino acids are in the C chain

Answer 3

35 amino acids

Question 4

How is insulin made today

Answer 4

Recombinant human DNA

Question 5

How was insulin made in the past

Answer 5

Bovine and porcine insulin

Question 6

What’s an insulin receptor

Answer 6

It has 2 alpha and 2 beta subunits. The b subunit has TK activity. There’s autophosphorylation of the beta unit.

Question 7

What’s the mechanism of insulin action

Answer 7

Insulin binds then the insulin undergoes autophosphorylation and then there’s an increase in intrinsic TK activity and finally, there’s phosphorylation of proteins

Question 8

What happens once insulin binds to the receptor

Answer 8

Enzyme activity, gene transcription, and protein synthesis increases. Insulin also regulated glucose and amino acids entering the cell.

Question 9

What does SGLT stand for?

Answer 9

Sodium glucose cotransporters

Question 10

Where are GLUT-1 located?

Answer 10

Brain, erythrocyte, ubiquitous

Question 11

Where GLUT-2 found?

Answer 11

Pancreas and liver

Question 12

Where’s GLUT-4 located?

Answer 12

Skeletal and cardiac muscle and fat

Question 13

What pathway does Insulin activate?

Answer 13

The phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathway

Question 14

How does Insulin effect muscle cells?

Answer 14

It increases the uptake of glucose and storage of glucose by muscle cells.

Question 15

Insulin enhances glucose uptake by

Answer 15

glucokinase (phosphorylating glucose to make glycogen)

Question 16

Insulin inactivates ____

Answer 16

Liver phosphorylase

Question 17

Lack of insulin activates what?

Answer 17

Glucose dephosphorylase which dephosphorylates glucose, which causes glycogen breakdown

Question 18

Insulin promotes what

Answer 18

The conversion of excess glucose into fatty acids in liver cells

Question 19

How are these fatty acids stored?

Answer 19

They’re packaged as triglycerides and are stored in fat cells

Question 20

What does insulin increase

Answer 20

Fat storage

Question 21

What does insulin produce with respects to fat metabolism?

Answer 21

Alpha-glycerol phosphate

Question 22

How does insulin effect protein metabolism and growth?

Answer 22

It increases amino acid transport into the cell and inhibits the breakdown of protein. It also increases the rate of transcription of selected DNA sequences.

Question 23

Explain the mechanism of insulin secretion by glucose?

Answer 23

Glucose enters pancreatic beta cells. This increases the ATP/ADP ratio. ATP sensitive K channels close and the membrane depolarizes. Voltage sensitive Ca channels open and Ca enters. This leads to exocytosis of insulin

Question 24

Glucagon is secreted by what

Answer 24

Alpha pancreatic cells

Question 25

What’s the mechanism of glucagon action

Answer 25

G protein coupled receptors, activation of adenylate cyclase, increase cAMP levels, which activates protein kinase A. This leads to enzyme and protein phosphorylation

Question 26

What does glucagon do?

Answer 26

It promotes glycogenolysis (breakdown of glycogen) and increases gluconeogenesis.

Question 27

How does glucagon cause glycogenolysis in the liver.

Answer 27

Through cAMP, protein kinase is activated, which activates phosphorylase B kinase. b is converted to Phosphorylase A. Glycogen is degraded to glucose-1-phosphate. Glucose is the. Dephosphorylated and released from liver cells into circulation