Estudio sobre síntesis de proteinas

[Hiperius]

Institute of Sports Medicine, Copenhagen, Bispebjerg Hospital, Denmark.

We hypothesized that an acute bout of strenuous, non-damaging exercise would increase rates of protein synthesis of collagen in tendon and skeletal muscle but these would be less than those of muscle myofibrillar and sarcoplasmic proteins. Two groups (n = 8 and 6) of healthy young men were studied over 72 h after 1 h of one-legged kicking exercise at 67% of maximum workload (W(max)). To label tissue proteins in muscle and tendon primed, constant infusions of [1-(13)C]leucine or [1-(13)C]valine and flooding doses of [(15)N] or [(13)C]proline were given intravenously, with estimation of labelling in target proteins by gas chromatography-mass spectrometry. Patellar tendon and quadriceps biopsies were taken in exercised and rested legs at 6, 24, 42 or 48 and 72 h after exercise. The fractional synthetic rates of all proteins were elevated at 6 h and rose rapidly to peak at 24 h post exercise (tendon collagen (0.077% h(-1)), muscle collagen (0.054% h(-1)), myofibrillar protein (0.121% h(-1)), and sarcoplasmic protein (0.134% h(-1))). The rates decreased toward basal values by 72 h although rates of tendon collagen and myofibrillar protein synthesis remained elevated. There was no tissue damage of muscle visible on histological evaluation. Neither tissue microdialysate nor serum concentrations of IGF-I and IGF binding proteins (IGFBP-3 and IGFBP-4) or procollagen type I N-terminal propeptide changed from resting values. Thus, there is a rapid increase in collagen synthesis after strenuous exercise in human tendon and muscle. The similar time course of changes of protein synthetic rates in different cell types supports the idea of coordinated musculotendinous adaptation.

Resumiento, este estudio demuestra que la síntesis de proteinas se mantiene por encima de los valores normales durante 72 horas y la síntesis de proteinas miofibrilares y colágeno muscular incluso más tiempo.

[Hiperius]

Perdón, no he puesto la fuente:

http://www.ncbi.nlm.nih.gov/pubmed/16002437

Saludos.

[karkian]

Bueno,en teoria esto viene a apoyar el entrenamiento de cuerpo entero 2 veces por semana??

síntesis de proteinas miofibrilares y colágeno muscular incluso más tiempo

Colageno??Interesante,eso no me lo sabia

[sebarc]

Si igualmente este es el único estudio que demuestra valores elevados por tanto tiempo, tal vez debido a que las piernas son musculos grandes. Por ejemplo en estos estudios el tiempo en que se mantuvo alta fue menor.

Can J Appl Physiol. 1995 Dec;20(4):480-6.Links
The time course for elevated muscle protein synthesis following heavy resistance exercise.
MacDougall JD, Gibala MJ, Tarnopolsky MA, MacDonald JR, Interisano SA, Yarasheski KE.

Department of Kinesiology, McMaster University, Hamilton, Ontario.

It has been shown that muscle protein synthetic rate (MPS) is elevated in humans by 50% at 4 hrs following a bout of heavy resistance training, and by 109% at 24 hrs following training. This study further examined the time course for elevated muscle protein synthesis by examining its rate at 36 hrs following a training session. Six healthy young men performed 12 sets of 6- to 12-RM elbow flexion exercises with one arm while the opposite arm served as a control. MPS was calculated from the in vivo rate of incorporation of L-[1,2-13C2] leucine into biceps brachii of both arms using the primed constant infusion technique over 11 hrs. At an average time of 36 hrs postexercise, MPS in the exercised arm had returned to within 14% of the control arm value, the difference being nonsignificant. It is concluded that following a bout of heavy resistance training, MPS increases rapidly, is more than double at 24 hrs, and thereafter declines rapidly so that at 36 hrs it has almost returned to baseline

J Appl Physiol. 1992 Oct;73(4):1383-8. Links
Changes in human muscle protein synthesis after resistance exercise.
Chesley A, MacDougall JD, Tarnopolsky MA, Atkinson SA, Smith K.

Department of Physical Education, McMaster University, Hamilton, Ontario, Canada.

The purpose of this study was to investigate the magnitude and time course for changes in muscle protein synthesis (MPS) after a single bout of resistance exercise. Two groups of six male subjects performed heavy resistance exercise with the elbow flexors of one arm while the opposite arm served as a control. MPS from exercised (ex) and control (con) biceps brachii was assessed 4 (group A) and 24 h (group B) postexercise by the increment in L-[1-13C]leucine incorporation into muscle biopsy samples. In addition, RNA capacity and RNA activity were determined to assess whether transcriptional and/or translational processes affected MPS. MPS was significantly elevated in biceps of the ex compared with the con arms of both groups (group A, ex 0.1007 +/- 0.0330 vs. con 0.067 +/- 0.0204%/h; group B ex 0.0944 +/- 0.0363 vs. con 0.0452 +/- 0.0126%/h). RNA capacity was unchanged in the ex biceps of both groups relative to the con biceps, whereas RNA activity was significantly elevated in the ex biceps of both groups (group A, ex 0.19 +/- 0.10 vs. con 0.12 +/- 0.05 micrograms protein.h-1.microgram-1 total RNA; group B, ex 0.18 +/- 0.06 vs. con 0.08 +/- 0.02 micrograms protein.h-1.microgram-1 total RNA). The results indicate that a single bout of heavy resistance exercise can increase biceps MPS for up to 24 h postexercise. In addition, these increases appear to be due to changes in posttranscriptional events.

Am J Physiol. 1997 Jul;273(1 Pt 1):E99-107.

Mixed muscle protein synthesis and breakdown after resistance exercise in humans.

Phillips SM, Tipton KD, Aarsland A, Wolf SE, Wolfe RR.

Metabolism Unit, Shriners Burns Institute, Galveston, Texas, USA.

Mixed muscle protein fractional synthesis rate (FSR) and fractional breakdown rate (FBR) were examined after an isolated bout of either concentric or eccentric resistance exercise. Subjects were eight untrained volunteers (4 males, 4 females). Mixed muscle protein FSR and FBR were determined using primed constant infusions of [2H5]phenylalanine and 15N-phenylalanine, respectively. Subjects were studied in the fasted state on four occasions: at rest and 3, 24, and 48 h after a resistance exercise bout. Exercise was eight sets of eight concentric or eccentric repetitions at 80% of each subject's concentric 1 repetition maximum. There was no significant difference between contraction types for either FSR, FBR, or net balance (FSR minus FBR). Exercise resulted in significant increases above rest in muscle FSR at all times: 3 h = 112%, 24 h = 65%, 48 h = 34% (P < 0.01). Muscle FBR was also increased by exercise at 3 h (31%; P < 0.05) and 24 h (18%; P < 0.05) postexercise but returned to resting levels by 48 h. Muscle net balance was significantly increased after exercise at all time points [(in %/h) rest = -0.0573 +/- 0.003 (SE), 3 h = -0.0298 +/- 0.003, 24 h = -0.0413 +/- 0.004, and 48 h = -0.0440 +/- 0.005], and was significantly different from zero at all time points (P < 0.05). There was also a significant correlation between FSR and FBR (r = 0.88, P < 0.001). We conclude that exercise resulted in an increase in muscle net protein balance that persisted for up to 48 h after the exercise bout and was unrelated to the type of muscle contraction performed.

J Physiol. 2006 Jul 27; [Epub ahead of print]

Resistance exercise increases AMPK activity and reduces 4E-BP1 phosphorylation and protein synthesis in human skeletal muscle.

Dreyer HC, Fujita S, Cadenas JG, Chinkes DL, Volpi E, Rasmussen BB.

University of Texas Medical Branch.

Resistance exercise is a potent stimulator of muscle protein synthesis and
muscle cell growth with the increase in protein synthesis being detected within 2-3 hours post-exercise and remaining elevated for up to 48 hours. However, during exercise muscle protein synthesis is inhibited. An increase in AMP-activated protein kinase (AMPK) activity has recently been shown to decrease mammalian target of rapamycin (mTOR) signalling to key regulators of translation initiation.

We hypothesized that the cellular mechanism for the inhibition of
muscle protein synthesis during an acute bout of resistance exercise in humans would be associated with an activation of AMPK and an inhibition of downstream components of the mTOR pathway (4E-BP1 and S6K1).

We studied 11 subjects (7 men, 4 women) before, during, and for two hours following a bout of resistance exercise. Muscle biopsies were collected at each time point from the vastus lateralis. We utilized immunoprecipitation and immunoblotting methods to measure muscle AMPKa2 activity, mTOR associated upstream and downstream signalling proteins, and stable isotope techniques to measure muscle fractional protein synthetic rate (FSR).

AMPKa2 activity (pmol*min-1*mg of protein-1) at baseline was 1.7 +/- 0.3, increased immediately post-exercise (3.0 +/- 0.6), and remained elevated at 1h post-exercise (P< 0.05). Muscle FSR decreased during exercise and was significantly increased at 1h and 2h post-exercise (P<0.05). 4E-BP1 phosphorylation at Thr37/46 was significantly reduced immediately post-exercise (P<0.05). We conclude that AMPK activation and a reduced phosphorylation of 4E-BP1 may contribute to the inhibition of muscle protein synthesis during resistance exercise. However, by 1-2h post-exercise muscle protein synthesis increased in association with an activation of PKB, mTOR, S6K1, and eEF2.

[caroan]

Perdonar por mi ignorancia, pero ¿podrías poner la traducción de este artículo para los que no sabemos inglés?
Gracias

[fedragon]

Perdonar por mi ignorancia, pero ¿podrías poner la traducción de este artículo para los que no sabemos inglés?

[Hiperius]

Muy buenos los estudios Sebarc, vienen hasta con porcentajes de sintesis de proteinas . Lo curioso es lo del estudio que he puesto yo, quizás sea por tratarse de las piernas, como dices, pero el último que has puesto ejercita el vasto lateral...

Perdonar por mi ignorancia, pero ¿podrías poner la traducción de este artículo para los que no sabemos inglés?
Gracias

Hazlo con el traductor de Google, así lo hacemos la mayoría . La traducción no es todo lo buena que nos gustaría, pero en artículos suele ser bastante aceptable.

Saludos.

[cargardu]

It has been shown that muscle protein synthetic rate (MPS) is elevated in humans by 50% at 4 hrs following a bout of heavy resistance training, and by 109% at 24 hrs following training

Esta es la tan llamada "ventana de la oportunidad" donde hay que comer muy bien.

We conclude that exercise resulted in an increase in muscle net protein balance that persisted for up to 48 h after the exercise bout and was unrelated to the type of muscle contraction performed.

We conclude that exercise resulted in an increase in muscle net protein balance that persisted for up to 48 h after the exercise bout and was unrelated to the type of muscle contraction performed.

Se entiende que es mejor dejar descansar el musculo 48hrs que 24 o 3 hrs de haberse ejercitado por lo que lei

Saludos

[sebarc]

Se entiende que es mejor dejar descansar el musculo 48hrs que 24 o 3 hrs de haberse ejercitado por lo que lei

Sería lo mas logico.