1-26 Pancreas DSA

Question 1

Describe the structure of insulin.

Answer 1

Peptide hormone

Consists of 2 straight chains:
A chain - 21 AAs
B chain - 30 AAs
linked by 2 disulfide bridges
 - additional linkage on A chain

Prohormone has additional connecting peptide (c peptide)

Question 2

What is the significance of C peptide as a diagnostic tool?

Answer 2

Provides basis for beta islet cell function for DMI, functional marker for endogenous insulin levels

Question 3

What is the effect that insulin has on glucose uptake and carbohydrate metabolism in muscle?

Answer 3

Increases glucose and AA uptake

Increases synthesis of mm tissue, glycogen

Increases K+ uptake

Question 4

What is the effect that insulin has on glucose uptake and carbohydrate metabolism in the liver?

Answer 4

Increases glucose and AA uptake

Increases glycogen synthesis

Increases protein synthesis

Decreases glycogenolysis

Question 5

What is the effect that insulin has on glucose uptake and carbohydrate metabolism in brain tissue?

Answer 5

All the suspected actions, as well as directly affects hypothalamic satiety center

Question 6

What is the effect that insulin has on glucose uptake and carbohydrate metabolism on adipocytes?

Answer 6

Increases fat deposition

decreases lipolysis

Question 7

What is the effect that insulin has on fat metabolism?

Answer 7

Increases fat deposition
decreases lipolysis

Decreases blood FFA concentrations

Question 8

What is the effect that insulin has on protein metabolism?

Answer 8

Decreases blood AA concentration

Anabolic effect

Question 9

What is the effect that insulin has on serum potassium homeostasis?

Answer 9

Promotes K+ uptake into cells

• increases activity of Na+/K+ ATPase
• protects against increase in serum K+ concentration

Question 10

What is the relationship between ketosis and insulin deficiency?

Answer 10

Lack of insulin leads to:

• increased blood glucose concentration
• increased lipolysis of fat
• increased blood FFA and ketoacid concentration
• decreased utilization of ketoacids by tissues

Increased ketoacids can cause diabetic ketoacidosis (DKA)

Question 11

What is the effect that DKA has on cell physiology? Acid-base status?

Answer 11

Shifts K+ out of cell

Reduces storage of sugars, AAs

Shifts acid base balance towards acid

Question 12

What is the effect that glucagon has on blood glucose concentrations?

Answer 12

Glucagon promotes utilization and mobilization of stored fuel

Generally promotes glycogen and mm breakdown to increase blood glucose, gluconeogenesis if needed