Short-term (5-10 days) calorie restriction (CR) downregulates muscle protein synthesis, with consumption of a high protein-based diet attenuating this decline. Benefit of increase protein intake is believed to be due to maintenance of amino acid-mediated anabolic signaling through the mechanistic target of rapamycin complex 1 (mTORC1), however, there is limited evidence to support this contenti...

Cachexia is a wasting syndrome associated with cancer, AIDS, multiple sclerosis, and several other disease states. It is characterized by weight loss, fatigue, loss of appetite, and skeletal muscle atrophy and is associated with poor patient prognosis, making it an important treatment target. Ghrelin is a peptide hormone that stimulates growth hormone (GH) release and positive energy balance th...

The reduced contribution of physical activity to daily energy expenditure and the accessibility to high-fat foods have put an excessive burden on energy balance, resulting in an increase in the prevalence of obesity throughout the world. In this context, fat gain can be seen as a natural adaptation to deal with a fattening lifestyle, since the hormonal adaptations that accompany fat gain favour...

Carnitine-dependent metabolic processes provide skeletal muscle with the ability to gain and to use energy from the environment, and relate mainly to the fatigue-resistant type I fibers, which are more dependent on oxidative metabolism than type II fibers, and are much higher in mitochondrial content. Functional specificities of carnitine and its system of proteins to intervene in the mitochond...

Skeletal muscle makes up approximately 40% of the total body mass, providing structural support and enabling the body to maintain posture, to control motor movements and to store energy. It therefore plays a vital role in whole body metabolism. Skeletal muscle displays remarkable plasticity and is able to alter its size, structure and function in response to various stimuli; an essential qualit...

This study tested the hypothesis that skeletal muscle mass is reduced in elderly women and men after adjustment first for stature and body weight. The hypothesis was evaluated by estimating appendicular skeletal muscle mass with dual-energy X-ray absorptiometry in a healthy adult cohort. A second purpose was to test the hypothesis that whole body 40K counting-derived total body potassium (TBK) ...

OBJECTIVE To investigate the metabolic response of skeletal muscle to exercise in patients with chronic heart failure and determine its relation to central haemodynamic variables. SETTING University hospital in Sweden. PARTICIPANTS 16 patients in New York Heart Association class II-III and 10 healthy controls. MAIN OUTCOME MEASURES Skeletal muscle biopsies were obtained from the quadricep...

Rose AJ, Richter EA. Regulatory mechanisms of skeletal muscle protein turnover during exercise. J Appl Physiol 106: 1702–1711, 2009. First published Janaury 29, 2009; doi:10.1152/japplphysiol.91375.2008.—Skeletal muscle protein turnover is a relatively slow metabolic process that is altered by various physiological stimuli such as feeding, fasting, and exercise. During exercise, catabolism of a...

As part of our research into the mechanisms of protein wasting and muscle weakness during critical illness, we here investigate various aspects of energy metabolism. Intraperitoneal injection of zymosan in rats leads to an acute phase of critical illness followed by a prolonged recovery phase. Previously we observed low activities of mitochondrial enzymes, reduced protein synthesis rates and lo...

Although it is well established that the lack of myostatin (Mstn) promotes skeletal muscle hypertrophy, the corresponding changes regarding force generation have been studied mainly in vitro and remain conflicting. Furthermore, the metabolic underpinnings of these changes are very poorly documented. To clarify this issue, we have investigated strictly noninvasively in vivo the impact of the lac...