Michael J Rennie

..It also deals with organ-specific protein metabolism of the splanchnic region, particularly the gut, liver and kidney...

..The examples given are from a variety of sources, including the work of the author, but the principles underlying the techniques are universally applicable to all metabolic investigations using tracers...

..There is no evidence that habitual exercise increases protein requirements; indeed protein metabolism may become more efficient as a result of training...

..This ability appears to be connected to the ability to sustain intracardiac ATP, phosphocreatine and glutathione...

..The maximal capacity for storage of amino acids as muscle protein probably sets an upper value on the extent to which amino acids can be stored after a single meal...

..The overexaggeration of the effects of growth hormone in muscle building is effectively promoting its abuse and thereby encouraging athletes and elderly men to expose themselves to increased risk of disease for little benefit...

..3 +/- 0.6 to 10 +/- 0.6 mg x kg(-1) x min(-1) (P < 0.05). In healthy people, AICAR acutely stimulates muscle 2DG uptake with a minor effect on whole-body glucose disposal...

..SB431542 can initially antagonize myostatin signaling, but long-term unexpected signaling effects occur. Muscle fibers hypertrophy, but their specific force decreases compared to control...

..We also explored the potential cardioprotective effects of glutamine in patients with chronic stable angina...

..Countermeasures to maximize muscle maintenance should target these deficits...

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..Given its ability to detect physiologically meaningful responses, the method should provide a new approach to studying the regulation of bone collagen turnover...

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..However, at insulin of <5 microU/mL, AAs appear to stimulate MPS without increasing mTOR signaling. Further increasing availability of insulin to postprandial values increases signaling activity, but has no further effect on MPS...

..We concentrate on the discussion of muscle protein metabolism because muscle is the predominant site of protein storage, and its integrity is mandatory for the maintenance of a good quality of life...

..Current evidence suggests that one of the major problems with loss of muscle during ageing is an inability of the tissue to respond adequately to increased availability of nutrients...

..05); calpain 1 mRNA increased 70% 72 h postexercise (P < 0.05) and at no other time. In conclusion, 5 days of creatine supplementation do not enhance anabolic signaling but increase the expression of certain targeted genes...

..These predictions should be tested by examining longitudinal effects of different modes of exercise and nutritional regimens on rehabilitation of muscle in transplant patients...

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..Therefore, there is no effect of menstrual cycle phase, at rest or in response to an acute bout of exercise, on myofibrillar protein synthesis and muscle collagen synthesis in women...

..026), but creatine had no effect on turnover in the postabsorptive or fed states. Thus any increase in muscle mass accompanying creatine supplementation must be associated with increased physical activity...

..01). Exercise increased the synthetic rates of myofibrillar and sarcoplasmic proteins by two- to threefold (P < 0.05), and leg phenylalanine balance became more positive, but creatine was without any anabolic effect...

..We propose that the stimulation of protein synthesis depends on the sensing of the concentration of extracellular, rather than intramuscular EAAs...

..Therefore, a more rapid rise in MPS after maximal LC could translate into greater protein accretion and muscle hypertrophy during chronic resistance training utilizing maximal LC...

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..CONCLUSION: The increase in lean body mass often reported after creatine supplementation could be mediated by signaling pathway(s) involving IGF and 4E-BP1...

..The similar time course of changes of protein synthetic rates in different cell types supports the idea of coordinated musculotendinous adaptation...

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..The present results indicate that high-intensity resistance exercise in the fasted state inhibits Akt/PKB and 4E-BP1 whilst concomitantly augmenting MAPK signalling and p70(s6k) on Thr421/Ser424...

..05) in both sexes. Thus, there is sexual dimorphism in MPS and its control in older adults; a greater basal rate of MPS, operating over most of the day may partially explain the slower loss of muscle in older women...

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..Recent application of stable isotope tracer techniques to measure human collagen synthesis has provided some insights into the role of nutrition and exercise on collagen turnover in the extracellular matrix of the musculoskeletal system...

..We conclude that smoking impairs the muscle protein synthesis process and increases the expression of genes associated with impaired muscle maintenance; smoking therefore likely increases the risk of sarcopenia...

..It is concluded that both in the resting state and after exercise, tendon collagen FSR is lower in women than in men, which may contribute to a lower rate of tissue repair after exercise...

..The molecular differences might contribute to mechanisms underlying the physiological adaptations seen with training using the two modes of exercise...