To identify early changes in gene expression during the fast-to-slow transition induced by chronic low-frequency stimulation, total RNA was extracted from 12-h-stimulated tibialis anterior (TA) muscles of rats and amplified by differential display RT-PCR. Among the signals of differentially expressed mRNAs, a cDNA ∼300 bp in length, which was almost undetectable in control TA muscles but promin...

AMP-activated protein kinase (AMPK), which was activated by an antihyperglycemic drug metformin, has been hypothesized to mediate metabolic adaptations. The purposes of the present study were 1) to confirm whether acute metformin administration induced AMPK phosphorylation and 2) to determine whether chronic metformin treatment increased the peroxisome proliferator-activated receptor-gamma coac...

Neurotrophins are a group of nerve growth factors with their protein structure. These proteins play an important role in the growth and metabolism of many cells and maintain nerve, muscle, synaptic potentials, and also helps reduce depression and apoptosis. The aim of this study was to evaluate the effect of 10 weeks low-intensity aerobic training and limited blood flow to the amount of protein...

Phospholipase A2 (PLA2) activity supports production of reactive oxygen species (ROS) by mammalian cells. In skeletal muscle, endogenous ROS modulate the force of muscle contraction. We tested the hypothesis that skeletal muscle cells constitutively express the calcium-independent PLA2 (iPLA2) isoform and that iPLA2 modulates both cytosolic oxidant activity and contractile function. Experiments...

Leucine and leptin play important roles in regulating protein synthesis and degradation in skeletal muscles in vitro and in vivo. However, the objective of the present study was to determine whether leptin and leucine function synergistically in regulating protein metabolism of skeletal muscles. In the in vitro experiment, C2C12 myotubes were cultured for 2 h in the presence of 5 mm-leucine and...

Rates of protein catabolism were compared in nongrowing skeletal muscle, in muscles undergoing work-induced hypertrophy, and in muscles growing in response to treatment with pituitary growth hormone. Hypophysectomized rats were injected initially with aH-leucine, and on subsequent days received unlabeled leucine and a high protein diet to minimize reutilization of the 3H-leucine. Rates of prote...

The glycosylation of dystroglycan is required for its function as a high-affinity laminin receptor, and loss of dystroglycan glycosylation results in congenital muscular dystrophy. The purpose of this study was to investigate the functional defects in slow- and fast-twitch muscles of glycosylation-deficient Large(myd) mice. While a partial alteration in glycosylation of dystroglycan in heterozy...

The effect of dietary administration of clenbuterol on soleus and extensor digitorum longus muscles was studied after 4 and 21 days. Both muscles showed an increase in wet weight with no significant change in total fibre number. After 4 days fibre cross-sectional areas were increased in soleus, but not in extensor digitorum longus, and after 21 days there was a change in fibre frequencies in ex...

In mice, certain proteins show a highly confined expression in specific muscle groups. Also, resting and exercise/contraction-induced phosphorylation responses are higher in rat skeletal muscle with low mitochondrial content compared to muscles with high mitochondrial content, possibly related to differential reactive oxygen species (ROS)-scavenging ability or resting glycogen content. To evalu...