Lecture 15 Flashcards
Impact of glucose in the digestive system
Glucose is the only nutrient that when it touches, it sends a signal to secrete insulin
Does glucose need to reach far in the digestive system to have an action?
Glucose is very instant in its action, does not need to reach into the intestine for the signal to happen
Where does the glucose go first in the body?
The muscles to see if needed and then the liver
Muscle ____ is a primary energy source
glycogen
2 areas where the glycogen can be found
Muscle and liver
Impact of AMPK on mTORC1
Inhibits the action of mTORC1 = affects protein synthesis
Which molecule promotes protein breakdown (by reducing PS)
AMPK
Does doing cardio before or after has an impact on protein synthesis? explain
Before is a little better for protein synthesis (but do it, better than nothing even if done after)
What is a stable isotope?
Naturally occurring atom
Contains an extra neutron
Stable (non-radioactive)
What isotope do we use to avoid having the radioactivity?
Carbon 13
What other technique than stable isotope can measure the rate of disappearance and appearance (synthesis vs breakdown)
Arterio-venous balance measurements across organs/limbs
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
Metabolic measurements of oxidation/energy expenditure using doubly labelled water
Using stable isotopes, how long does it take to reach the plateau?
2 hours approx.
What is the plateau in stable isotope process?
Determines the equilibrium between the actual protein and the stable isotope
What is the tracee vs tracer?
tracer is the stable isotope
tracee is the variable i want to measure
What is substrate-specific tracer?
Sterile infusions/pharmacy
Controlled environment
Acute measures
Single tracer required for each substrate of interest
NUTRITION
What is D2O?
Orally administered
Free living
Chronic measures
Labels multiple substrates
Depending on the duration
EXERCISE
Meaning of postabsorptive
Fasted state
Meaning of postprandial
After ingestion of the drink/meal
Name another method to measure muscle mass
D3 creatine or DXA scan
T or F: A stable isotope has 1 additional proton
FALSE, 1 additional NEUTRON
T or F: Stable isotopes could be infused or drank?
TRUE
In order to study MPS, what 2 things do you absolutely need?
Muscle biopsy
Stable isotope
T or F: Aerobic exercise could influence the expression of mTORC via the activation of AMPK
TRUE, because AMPK is expressed during aerobic exercise
How many weeks does it take to observe a significant increase in muscle mass via an MRI or a DXA scan?
6-8 weeks
GCMS is used to identiy compoud such as ____
atoms
T or F: The enrichment pool takes about 7h to get to the steady state
FALSE, takes 2h
T or F: to study the effects of food on MPS we need multiple biopsies
TRUE, at least two to compare fasted vs post-meal
What is the advantage of using D2O vs using substrate-specific tracer?
You are not on bedrest, free living environment
T or F: Anabolic resistance is the fact that older adults cannot absorb proteins the same way as young individual can
FALSE, there are other factors, such as anabolic resistance, it means more that they cannot reach this amount of protein synthesis
T or F: D3 creatine is another stable isotope used to measure total muscle mass
TRUE
T or F: Stable isotopes are also used to measure energy expenditure
TRUE
T or F: Muscle atrophy is way slower compared to muscle hypertrophy
FALSE, atrophy way faster, can start after 3 days of immobilization
