Skildum Metabolism Review

Question 1

What accounts for the majority of the chemical energy in your body?

Answer 1

Triacylglycerol

Example: Battery of the body is triacylglycerol, wire is ATP, and lightbulb is some process your body carries out

Question 2

24 hours after a meal, what is the major source of blood glucose?

Answer 2

Gluconeogenesis in the liver will be the major source of blood glucose!

Question 3

Can Acetyl coA be used as a substrate for gluconeogenesis?

Answer 3

No

Question 4

In a well nourished individual, as the length of fasting increases from overnight to one week, which one of the following is most likely to occur?

Answer 4

Muscle decreases its use of ketone bodies, which increases in the blood

(preserves ketone bodies for tissues that don’t have as much metabolic activity)

Question 5

Brain primary energy sources?

Answer 5

Glucose

Ketone bodies

Question 6

What are major products of the TCA cycle that are used in the electron transport chain to create ATP?

Answer 6

NADH and FAD(2H)

Question 7

Which of the 3 nutrient classes isn’t really stored in the body?

Answer 7

Amino acids

Question 8

What are the 4 important metabolic states?

Answer 8

Fed: Lasts 2-4 hours after a meal
Fasted: Overnight without eating
Starved: prolonged fasting
Hypercatabolic: trauma, sepsis–not related to meals

Question 9

What dominates the starvation state?

Answer 9

fatty acid metabolism

Question 10

Most important hormone regulating storage pathways in the fed state?

What is it directly responsive to?

Answer 10

Insulin

Concentration of glucose in blood

Question 11

Major regulator of catabolism in the fasted state?

Answer 11

Glucagon

Question 12

High carbs means more or less insulin?

Answer 12

More!

Question 13

High protein means more or less insulin? Glucagon?

Answer 13

Less insulin

More glucagon!

Question 14

What are the 2 biosynthetic pathways that produce glucose?

Answer 14

Glycogenolysis

Gluconeogenesis

Question 15

Metabolic pathways that store glucose? 4

Answer 15

FA biosynthesis
Cholesterol biosynthesis
Protein synthesis
Glycogenogenesis

Question 16

What cells release insulin?

Glucagon?

Answer 16

Insulin: Pancreatic Beta Cells
Glucagon: Alpha cells

Question 17

What do white adipose cells do with glucose?

What is done with this?

Answer 17

Ferment it to glycerol-3-phosphate

Backbone for triacylglycerol synthesis for storage in adipose!

Question 18

What do RBC do with glucose?

Answer 18

Ferment glucose to pyruvate and then export lactate

Question 19

Primary response of cardiac muscle to feeding?

Answer 19

Fatty acid beta oxidation

Question 20

What do intestinal epithelial cells do in reponse to feeding?

Answer 20

Convert GLUTAMINE, GLUTAMATE and ASPARTATE from diet into alpha-ketoglutarate which goes into TCA cycle

Question 21

What do colonocytes do in response to feeding?

Answer 21

Use short chain fatty acids produced by gut bacteria!

Question 22

Receptor for Glucagon? Following pathway after receptor is activated?

Answer 22

G-protein coupled receptor (7 transmembrane)

Ligand binding causes activation of adenylate cyclase, production of cAMP, and activation of PKA.

Question 23

When is Resting Energy Expenditure (REE) measured?

Answer 23

Fasted state

Question 24

What does gluconeogenesis use to produce glucose?

Answer 24

Carbon skeletons from a.a., lactate, and glycerol!

Question 25

What happens in skeletal muscle in response to FASTING?

Answer 25

Proteolysis produces free a.a. Branched chain a.a. are used as fuel! Alanine and glutamine are exported for use as gluconeogenic substrates by the liver.

Question 26

Primary amino acid used by gut epithelial cells?!

Answer 26

GLUTAMINE!

Question 27

White adipose tissue reponse to FASTING?

Answer 27

Lipolysis of triacylglycerol produces FA which are used by heart and liver...and Glycerol which is used for gluconeogenesis by the liver!

Question 28

Are glucose, insulin, and glucagon increased or decreased in response to fasting?

Answer 28

Glucose decreased Insulin decreased Glucagon increased

Question 29

What is the tissue with the most caloric density of which the body wants to degrade to provide energy during starvation? What is made from it?

Answer 29

FAT (adipose triacylglycerol) Ketone bodies!

Question 30

What is glucose spared for during starvation?

Answer 30

RBCs!

Question 31

What does cardiac muscle continue to use during starvation?

Answer 31

Fatty acids! | It doesn't like ketone bodies!

Question 32

What happens to skeletal muscle breakdown during starvation?

Answer 32

Decreases

Question 33

What organ decreases use of ketone bodies during starvation? What organ increases use of ketone bodies during starvation?

Answer 33

Skeletal muscle utilization decreases Brain utilization Increases!

Question 34

Urea excretion is highest at what point?

Answer 34

Fasting for 12 hours Note: Starvation at 5-6 weeks body is living primarily off of fatty acids and there is no nitrogen in fatty acids so there is no ned for urea excretion!

Question 35

What is hypercatabolism?

Answer 35

Rapid mobilization of stored fuels to provide energy for wound repair and immune system function. **Sustained muscle and organ protein breakdown!

Question 36

What activates hormone sensitive lipase to mobilize fatty acids from adipose?

Answer 36

Epinephrine

Question 37

What activates muscle proteolysis to mobilize a.a. from muscle (aa are used in liver for gluconeogenesis)?

Answer 37

Cortisol

Question 38

What activates hepatic glycogenolysis and gluconeogenesis?

Answer 38

Glucagon *Note: see lecture graph of timing of these hormones release. NE increases initially and becomes minimal 1-2 days after trauma etc.)

Question 39

Hypercatabolism changes of cytokines, glucagon, catecholamines, cortisol, insulin?

Answer 39

ALL INCREASED! | So gluconeogenesis occurs

Question 40

What do macrophages, lymphocytes, and fibroblasts use as fuel?

Answer 40

Glutamine from skeletal muscle breakdown!

Question 41

Nitrogen Balance formula

Answer 41

NB = Nitrogen intake - (urinary nitrogen + 2) **Add 2 because some Nitrogen is lost in sweat, sloughed skin and intestinal cells.

Question 42

What 2 types of cells are adapted to use glutamine as a fuel source?

Answer 42

Gut epithelial cells and lymphocytes

Question 43

What is the MOST IMPORTANT intracellular signaling molecule that leads to the liberation of stored chemical energy in response to glucagon?

Answer 43

Adenosine Monophosphate Kinase (AMP-K)

Question 44

What things are used by the liver for gluconeogenesis?

Answer 44

OUTSIDE SOURCES | AA, lactate, glycerol

Question 45

What does the liver use for glycogenolysis?

Answer 45

Glycogen that is stored in the liver

Question 46

Substrate for ketone body synthesis

Answer 46

Acetyl CoA produced by fatty acid beta oxidation

Question 47

Which amino acids does skeletal muscle use as fuel?

Answer 47

Branched chain

Question 48

What 2 AA are exported from skeletal muscle to be used as gluconeogenic substrates by the liver?

Answer 48

Alanine and glutamine

Question 49

Does the gut care if you are full or hungry?

Answer 49

Hell no! uses glutamine and glutamate regardless (from diet or from breakdown of muscle that is in blood pool)

Question 50

What does cortisol cause to happen in the flow phase of hypercatabolism?

Answer 50

Muscle protein breakdown to be used in hepatic gluconeogenesis

Question 51

What do lymphocytes use as fuel?

Answer 51

Glutamine

Question 52

How does glucagon respond in the flow phase of hypercatabolism?

Answer 52

Increases glycogenolysis and then switches to gluconeogenesis

Question 53

What do catecholamines promote in the ebb phase of hypercatabolism

Answer 53

Fat lipolysis

Question 54

Why do you need a little insulin around in hypercatabolism?

Answer 54

To make acute phase proteins in the liver that are essential for wound repair

Question 55

Nitrogen balance

Answer 55

Nitrogen intake - (urinary nitrogen +2,3, or 4) 2 if adult 3 if pediatric receiving TPN 4 if pediatric eating normally

Question 56

Refeeding syndrome

Answer 56

Death by MI

Question 57

Daily energy expenditure formula when recovering from trauma

Answer 57

DEE = REE x 1.6