Lecture 15

Question 1

Impact of glucose in the digestive system

Answer 1

Glucose is the only nutrient that when it touches, it sends a signal to secrete insulin

Question 2

Does glucose need to reach far in the digestive system to have an action?

Answer 2

Glucose is very instant in its action, does not need to reach into the intestine for the signal to happen

Question 3

Where does the glucose go first in the body?

Answer 3

The muscles to see if needed and then the liver

Question 4

Muscle ____ is a primary energy source

Answer 4

glycogen

Question 5

2 areas where the glycogen can be found

Answer 5

Muscle and liver

Question 6

Impact of AMPK on mTORC1

Answer 6

Inhibits the action of mTORC1 = affects protein synthesis

Question 7

Which molecule promotes protein breakdown (by reducing PS)

Answer 7

AMPK

Question 8

Does doing cardio before or after has an impact on protein synthesis? explain

Answer 8

Before is a little better for protein synthesis (but do it, better than nothing even if done after)

Question 9

What is a stable isotope?

Answer 9

Naturally occurring atom
Contains an extra neutron
Stable (non-radioactive)

Question 10

What isotope do we use to avoid having the radioactivity?

Answer 10

Carbon 13

Question 11

What other technique than stable isotope can measure the rate of disappearance and appearance (synthesis vs breakdown)

Answer 11

Arterio-venous balance measurements across organs/limbs

Question 12

Method that is based on the difference between the apparent turnover rates of the hydrogen and oxygen of body water as a function of CO2 production

Answer 12

Metabolic measurements of oxidation/energy expenditure using doubly labelled water

Question 13

Using stable isotopes, how long does it take to reach the plateau?

Answer 13

2 hours approx.

Question 14

What is the plateau in stable isotope process?

Answer 14

Determines the equilibrium between the actual protein and the stable isotope

Question 15

What is the tracee vs tracer?

Answer 15

tracer is the stable isotope
tracee is the variable i want to measure

Question 16

What is substrate-specific tracer?

Answer 16

Sterile infusions/pharmacy
Controlled environment
Acute measures
Single tracer required for each substrate of interest
NUTRITION

Question 17

What is D2O?

Answer 17

Orally administered
Free living
Chronic measures
Labels multiple substrates
Depending on the duration
EXERCISE

Question 18

Meaning of postabsorptive

Answer 18

Fasted state

Question 19

Meaning of postprandial

Answer 19

After ingestion of the drink/meal

Question 20

Name another method to measure muscle mass

Answer 20

D3 creatine or DXA scan

Question 21

T or F: A stable isotope has 1 additional proton

Answer 21

FALSE, 1 additional NEUTRON

Question 22

T or F: Stable isotopes could be infused or drank?

Answer 22

TRUE

Question 23

In order to study MPS, what 2 things do you absolutely need?

Answer 23

Muscle biopsy
Stable isotope

Question 24

T or F: Aerobic exercise could influence the expression of mTORC via the activation of AMPK

Answer 24

TRUE, because AMPK is expressed during aerobic exercise

Question 25

How many weeks does it take to observe a significant increase in muscle mass via an MRI or a DXA scan?

Answer 25

6-8 weeks

Question 26

GCMS is used to identiy compoud such as ____

Answer 26

atoms

Question 27

T or F: The enrichment pool takes about 7h to get to the steady state

Answer 27

FALSE, takes 2h

Question 28

T or F: to study the effects of food on MPS we need multiple biopsies

Answer 28

TRUE, at least two to compare fasted vs post-meal

Question 29

What is the advantage of using D2O vs using substrate-specific tracer?

Answer 29

You are not on bedrest, free living environment

Question 30

T or F: Anabolic resistance is the fact that older adults cannot absorb proteins the same way as young individual can

Answer 30

FALSE, there are other factors, such as anabolic resistance, it means more that they cannot reach this amount of protein synthesis

Question 31

T or F: D3 creatine is another stable isotope used to measure total muscle mass

Answer 31

TRUE

Question 32

T or F: Stable isotopes are also used to measure energy expenditure

Answer 32

TRUE

Question 33

T or F: Muscle atrophy is way slower compared to muscle hypertrophy

Answer 33

FALSE, atrophy way faster, can start after 3 days of immobilization