Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.3.3.1 (citrate synthase)
 4,488 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To evaluate the participation of proteins derived from mitochondrial genes in the adaptive response of skeletal muscle to increased contractile activity, we administered chloramphenicol (CAP; 200-1,000 mg.kg-1.day-1), an inhibitor of translation from mitochondrial ribosomes, to adult rabbits undergoing electrical stimulation of the tibialis anterior muscle of one hind limb. In unmedicated animals, 10 days of electrical stimulation increased maximum velocity (Vmax) of cytochrome oxidase and citrate synthase by 214 +/- 17 and 201 +/- 16% (P less than 0.01). In a dose-dependent manner, CAP abolished activity-induced increases in cytochrome oxidase Vmax, suggesting that augmented mitochondrial protein synthesis is necessary for the adaptive response of enzymes that require protein subunits encoded by mitochondrial genes. However, CAP failed to inhibit activity-induced changes in Vmax of enzymes derived exclusively from nuclear genes (citrate synthase and aldolase). CAP also failed to inhibit activity-induced increases in mRNA transcribed from the nuclear genes encoding beta-F1 ATPase or myoglobin, or from the mitochondrial genes encoding 12S rRNA, 16S rRNA, or cytochrome b. These latter findings suggest that mitochondrial translation products do not participate in pretranslational regulation of these nuclear or mitochondrial genes in response to changes in contractile activity of skeletal muscle.
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PMID:Effects of inhibition of mitochondrial protein synthesis in skeletal muscle. 289 13

Muscle microvascularization is usually quantified in transverse sections, in absolute terms (capillaries around fibres, CAF, or capillary-to-fibre ratio, C/F) or as CAF related to fibre area (CAF/area, CAFA). The capillary-to-fibre perimeter exchange ratio (CFPE) has been introduced in order to assess the role of the capillary-to-fibre interface in resistance to O(2) diffusion. The ratio between the length of capillaries in contact with fibres and fibre perimeter (LC/PF) has also been used as an index for capillary tortuosity. The possibility of change in capillary tortuosity with endurance training was not considered in previous studies. Consequently, this study investigated the effect of 14 weeks of endurance training on muscle microvascularization, including microvessel tortuosity, in 11 elderly men (8th decade). Microvessels were analysed using the CD31 antibody. Together with the significant increase in peak oxygen exchange and citrate synthase activity, there was a significant increase in C/F. While CFPE and CAFA remained unchanged, an important finding was the clear increase in LC/PF (56%; P < 0.001) for a same sarcomere length. We also found a strong correlation between oxidative enzyme activity and LC/PF both before and after training. These results indicate that endurance training induces significant remodelling in the microvessel network in elderly men and that an increase in the degree of microvessel tortuosity would be an important mechanism of adaptation to endurance training.
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PMID:Enhancement of microvessel tortuosity in the vastus lateralis muscle of old men in response to endurance training. 1457 92