Muscle Glycogen and Growth

Discussion in 'Diet & Nutrition' started by Martin Levac, Feb 4, 2008.

  1. quadancer

    quadancer New Member

    <div>
    (wisslewj @ Mar. 25 2008,23:24)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE"><div>
    (quadancer @ Mar. 25 2008,21:57)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">I'm investigating some of the conflicting info and checking into some lowfat BB'ers.</div>
    quad,

    low fat is one of the worst thing you can do for health and body building.  Saturated fat is absolutely necessary to move protein efficiently after digestion.

    Jeff</div>
    Oh dangit, I meant lowCARB. My bad. BTW, I did the lowfat diet all the way down to loss of memory and aching joints, so I agree with you on that. You were one of the BB'ers I referred to, W.
     
  2. pete69

    pete69 New Member

    Well, after sifting through pages of bullshit about low carbs and calories not mattering, can we get back to the topic on hand. Besides the initial study posted, this is the only other one i've found that shows that low glycogen might not be optimal for muscle hypertrophy.

    Antecdotally, people have bulked sucessfully with very low carb diets. Is this a factor of excess protein converting to glycogen, intramuscular triglycerides taking over some of the role of glycogen, glycogen doesn't matter that much in the scheme of things, lifting doesn't burn that much glycogen, or results WOULD have been better with post-workout carbs.

    Aaron, Dan, and feedback???
    Influence of muscle glycogen availability on ERK1/2 and Akt signaling after resistance exercise in human skeletal muscle
    Andrew Creer, Philip Gallagher, Dustin Slivka, Bozena Jemiolo, William Fink, and Scott Trappe
    Human Performance Laboratory, Ball State University, Muncie, Indiana

    Submitted 28 January 2005 ; accepted in final form 4 May 2005


    Two pathways that have been implicated for cellular growth and development in response to muscle contraction are the extracellular signal-regulated kinase (ERK1/2) and Akt signaling pathways. Although these pathways are readily stimulated after exercise, little is known about how nutritional status may affect stimulation of these pathways in response to resistance exercise in human skeletal muscle. To investigate this, experienced cyclists performed 30 repetitions of knee extension exercise at 70% of one repetition maximum after a low (2%) or high (77%) carbohydrate (LCHO or HCHO) diet, which resulted in low or high (174 or 591 mmol/kg dry wt) preexercise muscle glycogen content. Muscle biopsies were taken from the vastus lateralis before, 20 s after, and 10 min after exercise. ERK1/2 and p90 ribosomal S6 kinase phosphorylation increased (P 0.05) 10 min after exercise, regardless of muscle glycogen availability. Akt phosphorylation was elevated (P &lt; 0.05) 10 min after exercise in the HCHO trial but was unaffected after exercise in the LCHO trial. Mammalian target of rapamycin phosphorylation was similar to that of Akt during each trial; however, change or lack of change was not significant. In conclusion, the ERK1/2 pathway appears to be unaffected by muscle glycogen content. However, muscle glycogen availability appears to contribute to regulation of the Akt pathway, which may influence cellular growth and adaptation in response to resistance exercise in a low-glycogen state.
     
  3. quadancer

    quadancer New Member

    Now THAT'S what I'M talkin' about! (I could even understand it, heh)
    One thing about the last line there, Pete, is it saying that the glycogen itself isn't as important as we'd thought, but as a regulator of the other pathway, is now doing some unknown? regulation towards hypertrophy?
    I mean, it's a given that we're talking about a low glycogen state, so there is a change in the regulation; but to what direction?
     
  4. pete69

    pete69 New Member

    Quadancer, what the paper seems to show is that one pathway involved in muscle hypertrophy is unaffected by muscle glycogen, ERK1/2. But other pathways, AKT, mTor and others ARE affected by muscle glycogen, and that growth may be impaired by lifting weights in a glycogen depleted state.

    Here is the full text
    http://jap.physiology.org/cgi/content/full/99/3/950

    &quot;he mechanism preventing an increase in Akt phosphorylation after RE in the LCHO trial is not completely understood; however, AMP-activated protein kinase (AMPK) may play a role. AMPK is considered an energy-sensing protein kinase responding to changes in the cellular ATP-to-AMP ratio in response to muscle contraction (41). In rat skeletal muscle, pharmacological stimulation of AMPK has been shown to suppress phosphorylation of Akt, mTOR, and p70S6k (4). These data suggest that when skeletal muscle is under energetic stress, phosphorylation of the Akt pathway is suppressed, likely in an attempt to maintain cellular energy levels. In human skeletal muscle, previous studies showed that AMPK activation is elevated at rest and during exercise in a glycogen-depleted state&quot;

    &quot;Although these data would suggest a possible benefit from exercise in a low glycogen state, the present data suggest that exercise in a depleted state may attenuate growth by preventing the stimulation of proposed signaling pathways. Although care must be taken in making direct comparisons between data sets because of the different modes of exercise, there appears to be an interesting interaction between glycogen concentration and training adaptations, including growth and metabolic regulation, that warrants further investigation.

    In conclusion, on the basis of the present findings, it appears that mechanical stress associated with exercise is a powerful stimulator of ERK1/2 and p90rSk phosphorylation, independent of glycogen concentration. However, muscle glycogen availability appears to play a role in regulation of the Akt pathway, inasmuch as Akt phosphorylation was elevated only after RE in the HCHO trial. Thus the present findings suggest that although the ERK1/2 pathway may be unaffected by muscle glycogen, exercising in a glycogen-depleted or malnourished state may disrupt mechanisms involved with protein translation through the Akt pathway. In this manner, adaptations to an acute bout of exercise may be blunted.&quot;
     
  5. quadancer

    quadancer New Member

    First off, it was nice of them to admit and post this <div></div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">&quot;:Although care must be taken in making direct comparisons between data sets because of the different modes of exercise, there appears to be an interesting interaction between glycogen concentration and training adaptations, including growth and metabolic regulation, that warrants further investigation</div>&quot; I'd bet we have no idea just how much the different programs out here affect these properties.
    Secondly, I'm no labcoat, but they said &quot;glycogen-depleted or malnourished state&quot;. It occurs to me that if there is sufficient proteins and an energy source, are we really &quot;malnourished&quot; or not? (thinking Keto here...) You yourself mentioned that there are examples of people doing very well I would suppose in this very state.
    Just thinking aloud now. [​IMG]
     
  6. pete69

    pete69 New Member

    Quadancer, I think when the researchers were talking about malnourished what they really were referring to is low energy levels in the muscle cells. Once can be well fed and well nourished on a ketogenic diet, live their life perfectly normally, but if they are working out regularly, they may be in a glycogen depleted state.

    Now the question is does this low glycogen state have a negative effect on muscle growth. This SEEMS to be the case. Perhaps intramuscular triglycerides, which are burned to a greater degree when lifting with low glycogen, can act as a replacement. So far this doesn't seem to be the case.

    Now a very high protein, low carb diet (even with no carbs, very high protein usually prevents ketosis), might replace some of the muscle glycogen. The problem with this is that some of the research i've seen using very high protein, low carbohydrate intakes, blood glucose barely gets elevated. I haven't seen anything looking at replacing carbs with protein and muscle glycogen storage, but the excess protein of a keto/VLC diet seems to be increasing liver glycogen storage rather than muscle glycogen.

    This one is in rodents, but still may be relevant as it shows low energy levels in the cell causing a rise in AMPK, a fuel sensor, will inhibit some of the anabolic signals of muscle contractions.

    AMPK activation attenuates S6K1, 4E-BP1, and eEF2 signaling responses to high-frequency electrically stimulated skeletal muscle contractions
    David M. Thomson, Christopher A. Fick, and Scott E. Gordon

    Human Performance Laboratory, Department of Exercise and Sport Science, and Department of Physiology, East Carolina University, Greenville, North Carolina

    Submitted 24 August 2007 ; accepted in final form 2 January 2008

    Regulation of protein translation through Akt and the downstream mammalian target of rapamycin (mTOR) pathway is an important component of the cellular response to hypertrophic stimuli. It has been proposed that 5'-AMP-activated protein kinase (AMPK) activation during muscle contraction may limit the hypertrophic response to resistance-type exercise by inhibiting translational signaling. However, experimental manipulation of AMPK activity during such a stimulus has not been attempted. Therefore, we investigated whether AMPK activation can attenuate the downstream signaling response of the Akt/mTOR pathway to electrically stimulated lengthening muscle contractions. Extensor digitorum longus muscles (n = 8/group) were subjected to a 22-min bout of lengthening contractions by high-frequency sciatic nerve electrical stimulation (STIM) in young adult (8 mo) Fischer 344 x Brown Norway male rats. Forty minutes before electrical stimulation, rats were subcutaneously injected with saline or 5-aminoimidazole-4-carboxamide-1–4-ribofuranoside (AICAR; 1 mg/g body wt), an AMPK activator. Stimulated and contralateral resting muscles were removed at 0, 20, and 40 min post-STIM, and AMPK, acetyl CoA carboxylase (ACC), Akt, eukaryotic initiation factor 4E-binding protein (4E-BP1), 70-kDa ribosomal protein S6 kinase (S6K1), and eukaryotic elongation factor 2 (eEF2) phosphorylations were assessed by Western blot. AICAR treatment increased (P &amp;#8804; 0.05) post-STIM AMPK (Thr172) and ACC phosphorylation (Ser79/221), inhibited post-STIM S6K1 (Thr389) and 4E-BP1 (gel shift) phosphorylation, and elevated post-STIM eEF2 phosphorylation (Thr56). These findings suggest that translational signaling downstream of Akt/mTOR can be inhibited after lengthening contractions when preceded by AMPK activation and that energetic stress may be antagonistic to the hypertrophic translational signaling response to loaded muscle contractions.
     
  7. quadancer

    quadancer New Member

    Hate me for this, but it's gone over my head. I wondered about the liver glycogen myself since that's what fructose tends to elevate instead of muscle glycogen - but apparently for some reason, this problem is countered in some other way in the process of ketosis that I don't understand. All I can do is direct you to the &quot;Straddling the fence&quot; thread I started and the attached article. I need to reread it myself.

    http://www.hypertrophy-specific.info/cgi-bin....y135194
     
  8. jstrick2

    jstrick2 New Member

    This is quite possibly one of the most idiotic threads I have for some reason forced myself to suffer through.

    The way Martin has narrowed his sources of information and created pure idiocy is almost commendable.


    To put that much time into it... quite lol

    I salute the efforts in the face blatant information proving counter to your claims.  I suggest more use of random tidbits from books, your own personal experiences, etc to serve as support for Taubes book.  Kudos.


    Its like a new age form of trolling. Take note fellow and future trolls, behold the future!

    [​IMG]
     
  9. Martin Levac

    Martin Levac New Member

    <div>
    (jstrick2 @ Apr. 09 2008,16:38)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">This is quite possibly one of the most idiotic threads I have for some reason forced myself to suffer through.

    The way Martin has narrowed his sources of information and created pure idiocy is almost commendable.


    To put that much time into it... quite lol

    I salute the efforts in the face blatant information proving counter to your claims. I suggest more use of random tidbits from books, your own personal experiences, etc to serve as support for Taubes book. Kudos.


    Its like a new age form of trolling. Take note fellow and future trolls, behold the future!

    [​IMG]</div>
    Irony again. Idiots can't seem to understand that every time they post some stupid comment about how stupid the thread is, they make the thread even more stupid. That's how stupid you are, dude. You are so stupid, you can't see how stupid you are.

    I don't hold it against you. It's not your fault. Maybe your parents are related. Who knows.
     
  10. dkm1987

    dkm1987 New Member

    Pete,

    AKT is only one path and the availablity or lack of glycogen may not impact other paths at all.

    In several newer papers, looking strictly at mechanical loading, mTOR and it's down stream activity on other cellular mechanisms were not impaired even though AKT phosphorylation was viritually non existant. That leads us to the possibility that the chain of events coming out of AKT activation works w or w/o AKT. Just another sign of the vastness of sensing molecules and how the system interacts/intercepts or diverges based on the various stimuli.

    Back to original topic, it really only makes sense when you look at how the energy required for ATP is of utmost importance and priority so of course if glycogen is low the bodies first action is to use what is available for ATP homeostatis and stall the PS chain (highly energetically demanding) and AMPK is important in that process.
     

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