J. H. Coakley

Exercise induced activation of the branched-chain 2-oxo acid dehydrogenase in human muscle

SummaryThe present study was conducted to investigate the metabolic regulation of the oxidation of branched-chain amino acids (BCAA) by exercise in human skeletal muscle. Five trained male volunteers were exercised on a cycle ergometer at 70%±10% (mean±SD) of their maximal oxygen consumption % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Jf9qqqrpepC0xf9qiW7rqqrFfpeea0xe9LqFf0x% c9q8qqaqFn0dXdir-xcvk9pIe9q8qqaq-xir-f0-yqaqVeLsFr0-vr% 0-vr0xc8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaacaGGOaGabm% OvayaacaWaaSbaaSqaaGqaaiacCb4FpbWaaSbaaWqaaiaa-jdacaWF% TbGaa8xyaiaa-HhaaeqaaaWcbeaakiaacMcaaaa!41C5!

The metabolic consequences of reduced habitual activities in patients with muscle pain and disease

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Selenium metabolism and supplementation in patients with muscular dystrophy

. Percutaneous quadriceps muscle biopsies were obtained under local anaesthesia at rest and after 30 and 120 min of exercise. In the muscle samples the active and total amount of the branched-chain 2-oxo acid dehydrogenase complex (BC-complex), the regulatory enzyme in the oxidative pathway of the BCAA, were measured. Glycogen content and activity of mitochondrial marker enzymes were also measured. Blood samples were obtained every 20 min for the measurement of metabolites. Heart rate and rated perceived exertion on the Borg scale were recorded every 10 min. At rest 4.0%±2.5% of the BC complex was active, after 30 min of exercise 9.9%±9.0% and after 120 min 17.5%±8.5% (mean±SD). Exercise did not change the total activity. The largest activation was seen in two of the subjects who developed higher blood lactates early on during exercise and decreased their muscle glycogen more (indications of anaerobic metabolism). These data demonstrate that in trained individuals significant increases in the activity of the BC-complex occur only after prolonged intense exercise. In spite of the 4-fold activation, the data support the classical view that amino acids and protein do not contribute substantially as an energy source during exercise, since % MathType!MTEF!2!1!+-% feaafiart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr% 4rNCHbGeaGqiVu0Jf9qqqrpepC0xf9qiW7rqqrFfpeea0xe9LqFf0x% c9q8qqaqFn0dXdir-xcvk9pIe9q8qqaq-xir-f0-yqaqVeLsFr0-vr% 0-vr0xc8meaabaqaciGacaGaaeqabaWaaeaaeaaakeaaceWGwbGbai% aadaWgaaWcbaacbaGaiWfG-9eadaWgaaadbaGaa8Nmaaqabaaaleqa% aaaa!3D99!

Effect of mazindol on dystrophic mice and on growth in young rats

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Metabolism of branched-chain amino acids and ammonia during exercise : clues from McArdle's disease

increased more than 20-fold.

Molecular heterogeneity in McArdle's disease

The similarity in clinical features of X-linked Becker muscular dystrophy (BMD) and the autosomal recessive limb-girdle (LGD) type of adult muscular dystrophy makes differential diagnosis of the isolated male case difficult. DNA probes complementary (cDNA) to the Duchenne/Becker muscular dystrophy gene product, dystrophin, can detect molecular deletions in 60-70% of affected subjects. Thirty-three patients with BMD or LGD (thirty isolated and three with an affected brother) were screened with a panel of cDNA probes for the whole dystrophin gene. Deletions were found in thirteen of eighteen (72%) patients with a diagnosis of BMD. Deletions were also found in four of the fifteen (27%) patients previously thought to have LGD, who were therefore reclassified as having BMD. All male patients with progressive muscular dystrophy of limb-girdle pattern should be routinely screened with these cDNA probes as a useful adjunct to their clinical diagnosis since the results have important implications for genetic counselling of affected families.