I just read about this, and found it fascinating. If high glucose levels do indeed blunt gene expression after exercise, then I guess most of us are doing PWO nutrition all wrong. Or is the anabolic effect of an insulin surge even more beneficial?
It would be great if JB could comment on this.
This is from Arthurdevany.com:
"Gene Expression and Muscle Glycogen
I said it before and I say it again now: filling your muscles with glycogen is nonsense. I have pointed out how gene expression is altered by your activity and your stores of nutrients, among other things. And I have argued that body builders and runners and others who rush to refill their muscle with glycogen right after a work out are actually turning down the training response.
Now, here is an interesting article that measures gene expression and it shows that it is turned down when your muscles contain a lot of glycogen. You reduce the magnitude of the adaptive response to exercise if you are in a hurry, as so many body builders and runners are, to replenish your glycogen stores. They are not thinking at all about gene signaling and adaptation. They are in the linear thinking mode and must reason in a simple (dumb) inventory framework. Use up the glycogen and refill it right away.
This is one of those non-linearities. If you replace the glycogen right away you turn off the gene expression that builds more muscle and does other complex things in muscle tissue. Note the article speaks of TRANSIENT genetic induction, not a steady state. Inducing transients is the essence of the intermittent approach of Evolutionary Fitness.
The abstract follows… There is something very important about uncoupling protein UCP3 that only I and a few others know about and I may be the only person to incorporate respiratory chain uncoupling in anti-aging model and practice.
Read More ?
Influence of pre-exercise muscle glycogen content on exercise-induced transcriptional regulation of metabolic genes
Henriette Pilegaard *, Charlotte Keller ?, Adam Steensberg ?, J?rn Wulff Helge ?, Bente Klarlund Pedersen ?, Bengt Saltin ? and P. Darrell Neufer ?
The Copenhagen Muscle Research Centre, * The August Krogh Institute, University of Copenhagen, Denmark, ? Department of Infectious Diseases, University of Copenhagen, Denmark, ? Rigshospitalet, University of Copenhagen, Denmark and ? The John B. Pierce Laboratory and Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
Transcription of metabolic genes is transiently induced during recovery from exercise in skeletal muscle of humans. To determine whether pre-exercise muscle glycogen content influences the magnitude and/or duration of this adaptive response, six male subjects performed one-legged cycling exercise to lower muscle glycogen content in one leg and then, the following day, completed 2.5 h low intensity two-legged cycling exercise. Nuclei and mRNA were isolated from biopsies obtained from the vastus lateralis muscle of the control and reduced glycogen (pre-exercise glycogen = 609 ? 47 and 337 ? 33 mmol kg-1 dry weight, respectively) legs before and after 0, 2 and 5 h of recovery. Exercise induced a significant (P < 0.05) increase (2- to 3-fold) in transcription of the pyruvate dehydrogenase kinase 4 (PDK4) and uncoupling protein 3 (UCP3) genes in the reduced glycogen leg only. Although PDK4, lipoprotein lipase (LPL) and hexokinase II (HKII) mRNA were elevated in the reduced glycogen leg before exercise, no consistent difference was found between the two legs in response to exercise. In a second study, six subjects completed two trials (separated by 2 weeks) consisting of 3 h of two-legged knee extensor exercise with either control (398 ? 52 mmol kg-1 dry weight) or low (240 ? 38 mmol kg-1 dry weight) pre-exercise muscle glycogen. Exercise induced a significantly greater increase in PDK4 transcription in the low glycogen (> 6-fold) than in the control (< 3-fold) trial. Induction of PDK4 and UCP3 mRNA in response to exercise was also signficantly higher in the low glycogen (11.4- and 3.5-fold, respectively) than in the control (5.0- and 1.7-fold, respectively) trial. These data indicate that low muscle glycogen content enhances the transcriptional activation of some metabolic genes in response to exercise, raising the possibility that signalling mechanisms sensitive to glycogen content and/or FFA availability may be linked to the transcriptional control of exercise-responsive genes."