Balancing atrophy/hypertrophy

Hi Dan, I came across an interesting review of work on the ubiquintin-proteasome pathway. It is the first time I have looked into this area and it has brought up some questions. I will highlight some sentences to summarise the paper.
 
Cellular adaptation requires selective degradation of existing proteins, a process primarily regulated by the Ubiquintin-proteasome pathway. To meet this challenge, general activity of the pathway is increased.
Excercise effects on the Ub-pathway are task specific. For example, the authors conclude that ...eccentric exercise produces the most robust changes and concentric exercise appear to have less effect.
The ubiquintin- pathway appears to be responsible for specific intracellular protein degradation. Increase activity of the Ub-pathway is common in conditions which elicit increased muscular proteolysis including starvation and a variety of excercise conditions. Exercise appears to be related to a three phase Ub-pathway response. Phase one begins immediately following initiation of exercise and transiently (minutes to hours) increases the activity of the UB-pathway. This phase reverses as exercise has ended. Phase 2, occuring 6-24 hours following exercise involves an increased expression of the Ub-pathway and is thought to be involved in remodelling of damaged muscle tissue. Phase 3 occurs days to weeks after exercise and is accociated with a return of Ub-proteasome expression to base line levels.
 
Sustained decreases or increases in physical activity cause muscle fibres to adapt, altering protein expression and fibre size. The outcome of these adaptive responses, atrophy vs. hypertrophy reflects the net balance between protein degradation and protein synthesis. Atrophy requires that protein degradation exceed resynthesis. In muscle hypertropy, the opposite is true. Amino acid supplements delivered before and after exercise markedly increases protein balance, and this increase is associated with greater blood flow to the muscle tissue.
And interestingly, the response of the pathway to a change in muscle use appears to vary according to intensity and duration of the intervention.  
Michael B. Reid http://ajpregu.physiology.org/cgi/content/abstract/288/6/R1423
 
I would to ask:
Briefly, what are the major processes in balancing catabolism and anabolism, how are they tied into each other and, how big a part does the ubiquintin-pathway play in this (if there are others). It does appear to have a major role and with understanding this more I could employ some better eating-exercise habbits (hopefully in addition to the basics).
Muscle adaptation requires first the degradation of existing proteins via the Ub-pathway. Hypertrophy is when protein synthesis exceeds protein degradation. How do factors; intensity and duration specificaly relate to the balance between atrophy and hypertrophy?
 
Thanks  
 

Good work on tackling the article!
 
I will give you more specific answers later.  Have to run and take finals.
 
As you read, The ubiquitin-proteasome pathway regulates proteolysis (breaking down of proteins) in mammalian cells by attaching ubiquitin polymers to damaged proteins; this targets the protein for degradation via the 26S proteasome.
 
The point of the mechanism is to tag damaged proteins for degradation or replacement or, to simply tag proteins deemed no longer necessary to be broken down in the normal turnover of cells.
 
If you do not train, there tends to a gradual decrease in muscle, as other pathways that increase proteins in muscle are not stimulated. The general idea is that we want protein aggregation to outweigh protein degredation.
 
This is a good mechanism, but as bodybuilders we use strategies to minimize the unnecessary loss of proteins.
 
There are methods to minimize the loss of protein due to various factors. Most of these are discussed regularly, and they indirectly address this and other mechanisms in particular,
 
Keep in mind, this is a microscopic view of one player in a larger orchestra.  We could look at certain gene expressions or other players and try to understand how to alter them to accomplish our goals better, and there are researchers doing that work.  But the end result is that we develop the best rest, training, recovery, mind, nutrition, and supplementation  regimen that we can devise.

By providing pre and post workout proteins as well as carbs, you can lower the amount of muscle protein that is degraded and increase the rate of protein aggregation (up to a certain limit.)  By providing adequate protein, fats and carbs at intervals (frequent feeding) throughout the day as well as specific timed meals, you can continue the trend.  Too much protein intake UPREGULATES other pathways that degrade protein before it is used for repair or energy.  That is a tradeoff many people make without knowing it.

It should be noted that, in general, in highly trained and conditioned individuals, the expression of this mechanism is altered.   Adapting your lifestyle to favor higher growth related hormones decreases the rate of muscle degradation as well as increasing the rate of aggregation.

More later!

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Much appreciated.

Dan I've been reading your threads.

I must say - you definitely know your stuff man.

Perhaps the most knowledgable guy I've ever seen on a bodybuilding forum.

Thanks MVP. 

It is based on a lifetime of passion and study coupled with my love of the sport and of sharing what I have learned...

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No problem man you're a human genious.

I start cutting in two months, and I just read your "losing fat" article on your signature and I believe my IQ went up about 60 points.

Good read and extremely helpful.  Thanks so much for your info.

Personal Trainer/Nutrition Consultant

i agree. very well-read i should say.
you know your stuff man! and thanks much for sharing and taking your time to respond.
i have verified your inputs and indeed you are on the right track when it comes to medical-related
advice

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