Seminars Flashcards
What is the fractional muscle protein turnover
balance of synthesis and breakdown in the body
What is the rate of fractional muscle protein turnover
1-2% a day = ~300-600g of protein.
What is a tracer
a chemically identical compound, which is distinct in some way i.e. changing isotope
Give 2 advantages of stable isotopes
Non-Radioactive No risk Naturally occurring Provides dynamic measure of metabolism Behave biologically the same
Give 2 disadvantages of stable isotopes
Can be invasive Expensive Long test days involved Biological analyses are expensive/specialist May have some side-effects
Why is IV administration prefered to oral
there is a steady infusion rate compared with oral
Describe the process of isotope measurement
To measure isotope levels, a pre-cursor is taken i.e. blood sample to identify the amino acids. Then a muscle biopsy is taken to sample the proteins and analysed with mass spectrometry.
You can then calculate whole-body protein metabolism, protein digestion, tissue protein synthesis, and the incorporation of amino acids into body proteins.
How is FSR calculated
FSR = deltaEprecursor/Eprecursor x time between biopsies X100%
What does Eprecursor (FSR calculation mean)
average enrichment in precursor pool
State 4 of Hills Causal criteria
Strength. Consistency. Specificity. Temporality. Biologic gradient. Plausibility. Coherence. Experimental evidence. Analogy.
What is HMB
a metabolite of leucine
Give 2 effects of HMB
- Increases protein synthesis of myofibrils
- Changes phosphorylation of downstream messengers
- Repair tissue, so muscles less prone to damage (OA reductase)
- Stops degradation of myofibrillar proteins
How does protein degradation occur
Ubiquitin is tagged to a protein, which is sent to the proteasome for degradation
Why don’t we want to prevent the breakdown of protein
We don’t want to stop the breakdown of muscle protein, as it is essential for adaptation
What beneficial effect does green coffee have
Anti-hypertensive
