Endocrine at Home

Question 1

Diabetes (def)

A group of disorders of (1), which is a syndrome characterized by (2) and (3)

Answer 1

(1) glucose homeostasis
(2) chronic hyperglycemia
(3) other disturbances in carbohydrate and fat metabolism

Question 2

Three interrelated processes of glucose regulation

Answer 2

(1) Gluconeogenesis
(2) Glycgen synethesis, glycogenolysis
(3) Insulin mediated regulation

Question 3

Gluconegenesis

• What is it
• Where

Answer 3

• Glucose production

- In the liver (and sometimes kidneys)

Question 4

Glycogen synthesis / glycogenolysis

• What is it
• Where

Answer 4

• Glucose storage

- Skeletal muscle, liver

Question 5

Insulin-mediated glucose regulation

• What is it
• Where

Answer 5

• Glucose uptake

- Peripheral tissue (esp skeletal muscle, fat and liver)

Question 6

What are the two stages of normal fluctuations in plasma glucose?

Answer 6

• Absorptive state

- Post-absorptive state

Question 7

What is the body’s priority during the absorptive state?

Answer 7

To decrease plasma glucose (prevent marked elevation)

Question 8

What 5 mechanisms does the body employ during the absorptive state?

Answer 8

• Decrease in gluconeogenesis
• Decreasse in genolysis
• Increase in tissue permeability to glucose (especially skeletal muscle mediated by insulin)
• Increase in glycogen synthesis (glucose storage)
• Limit use of fat as primary energy source / increase lipogenesis (fat storage)

Question 9

What is the body’s priority during the post-absorptive state?

Answer 9

To increase / maintain plasma glucose (prevent marked drop)

Question 10

What 4 mechanisms does the body employ during the post-absorptive state?

Answer 10

• Glycogenolysis
• Gluconeogenesis
• Limit access to glucose to only those tissues that absolutely need it like the CNS (insulin level drops)
• Use of fat as primary energy source (lipolysis)

Question 11

Why does the body use fat as the primary energy source during the post-absorptive state?

Answer 11

To conserve glucose for use by CNS and other tissue that can’t use fat as an energy source

Question 12

Three ways glucose gets into and out of the cell:

Answer 12

1) Facilitated diffusion
2) Requires a protein transporter (glucose transporters
3) Requires a concentration gradient

Question 13

Two glucose transporters (of the 4)

Answer 13

• Glut-1 Transporters

- Glut-4 tranporters

Question 14

Four characteristics of Glut-1 Transporters

Answer 14

• Allow glucose to enter the cell
• Constitutively expressed (on all cells, but in low density)
• Responsible for low levels of basal glucose uptake required to sustain energy generation by all cells

Question 15

When is expression of Glut-1 Transporters Increased?

Answer 15

Expression is increased with prolonged fasting and decreased with persistent exposure to excessive glucose

Question 16

Where are glut-4 transporters expressed? (3)

Answer 16

• Expressed in cardiac, sk muscle, adipose, liver tissue

Question 17

What are Glut 4 Transporters responsible for?

- Mechanism

Answer 17

• Responsible for insulin stimulated uptake of glucose

Question 18

Mechanism of Glut-4 Transporters

Answer 18

• PI-3K signaling pathway enables GT4 receptor to get inserted → glucose uptake

Question 19

Events stimulated by the PI-3K pathway

Answer 19

• Enables GT4 Receptor to get inserted → Glucose uptake
• Proliferation
• Synthesis of lipids, protein and glycogen
• All of the enzymes to convert glucose into triglycerides
• All of the enzymes needed to stimulate glycogen

Question 20

What event does MAPK help the PI-3K pathway with?

Answer 20

Proliferation and cell growth

Question 21

Along with PI-3K and MAPK, what else acts as a growth factor?

Answer 21

INSULIN

Question 22

What are the exocrine components of the pancreas? (1)

Answer 22

Pancreatic ducts

Question 23

What are the endocrine components of the pancreas, and what does each produce? (2)

Answer 23

• Alpha cells (glucagon)

- Beta cells (insulin)

Question 24

Characteristics of Glucagon (5)

Answer 24

o	Produced by alpha cells
o	Hormone of the post-absorptive state
o	Enzymes necessary for glycolysis 
o	Enzymes that inhibit lipogenesis
o	Causes retraction of gluten 4 inhibitors

Question 25

Characteristics of Insulin (6)

Answer 25

o Produced by beta cells
o Hormone of the absorbtive state
o Inhibits enzymes for gluconeogenesis and glycolysis
o Allows for insertion of gluten 4 transporters (increases permeablility to glucose in skeletal muscles, fat, liver)
o Increase in glucose syntehsis
o Promotes lipogenesis, inhibits lipolysis: signals to fat cells to maintain their density