scholarly journals In vitro acute effects of free fatty acids on protein degradation in young rat skeletal muscle

2008 ◽  
Vol 22 (S1) ◽  
Author(s):  
Lidiany Góis ◽  
Neusa Maria Zanon ◽  
Renato Helios Migliorini ◽  
Isis do Carmo Kettelhut
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Protein Degradation ◽  
Acute Effects ◽  
Rat Skeletal Muscle ◽  
Young Rat

scholarly journals Activation of the multicatalytic proteinase from rat skeletal muscle by fatty acids or sodium dodecyl sulphate

1985 ◽  
Vol 228 (1) ◽  
pp. 171-177 ◽  
Author(s):  
B Dahlmann ◽  
M Rutschmann ◽  
L Kuehn ◽  
H Reinauer
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Conformational Changes ◽  
Sodium Dodecyl Sulphate ◽  
Muscle Protein ◽  
Sodium Dodecyl ◽  
Rat Skeletal Muscle ◽  
Multicatalytic Proteinase

A multicatalytic proteinase from rat skeletal muscle contains active site(s) catalysing the degradation of benzoyl-Val-Gly-Arg 4-methyl-7-coumarylamide, succinyl-Ala-Ala-Phe 4-methylcoumarylamide and [14C]methylcasein as well as benzyloxy-carbonyl-Leu-Leu-Glu 2-naphthylamide. These activities are 7-14-fold activated by 1 mM-sodium dodecyl sulphate. The activation leads to a higher susceptibility to the proteinase inhibitor chymostatin and to a lower ability to be inhibited and precipitated by antibodies raised against the non-activated enzyme. Since no changes in Mr or subunit composition were observed in the SDS-activated form, some conformational changes seem to occur during the activation step. More pronounced activation was observed in the presence of physiological concentrations of fatty acids; oleic acid at 100 microM concentrations stimulated the proteinase about 50-fold. In contrast with the non-activated proteinase, the activated enzyme considerably degrades muscle cytoplasmic proteins in vitro. Thus it is not unlikely that, in vivo, potential activators such as fatty acids can induce the multicatalytic proteinase to participate in muscle protein breakdown.

Relationship between plasma free fatty acids and uncoupling protein-3 gene expression in skeletal muscle of obese subjects: in vitro evidence of a causal link

2002 ◽  
Vol 57 (2) ◽  
pp. 199-207 ◽  
Author(s):  
Paolo Sbraccia ◽  
Monica D’Adamo ◽  
Frida Leonetti ◽  
Angela Buongiorno ◽  
Gianfranco Silecchia ◽  
...  
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Uncoupling Protein ◽  
Causal Link ◽  
Plasma Free Fatty Acids ◽  
Uncoupling Protein 3 ◽  
Obese Subjects

Effect of high FFA on glycogenolysis in oxidative rat hindlimb muscles during twitch stimulation

1996 ◽  
Vol 270 (4) ◽  
pp. R766-R776 ◽  
Author(s):  
D. J. Dyck ◽  
S. J. Peters ◽  
P. S. Wendling ◽  
L. L. Spriet
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acids ◽  
Free Fatty Acids ◽  
Glucose Uptake ◽  
Rat Skeletal Muscle ◽  
Acetyl Coa ◽  
Hindlimb Muscles ◽  
Rest Perfusion ◽  
Wide Range ◽  
Glycogen Sparing

The effect of elevated free fatty acids (FFA) on carbohydrate (CHO) utilization in the oxidative muscles of the isolated hindlimb was determined using twitch contraction paradigms evoking a wide range of O2 uptakes and glycogenolysis. The hindlimb was perfused with either 0 or 1.8 mM FFA for 10 min at rest and then subjected to 20 min of stimulation at 0.4, 0.7, 1, 2, 3, or 4 Hz. Soleus (Sol), plantaris (Pl), and red gastrocnemius (RG) were sampled after rest perfusion or stimulation. FFA had little effect on glycogenolysis during stimulation, although glycogen sparing occurred with one of the lesser intensity protocols in each muscle (Sol, 0.4 Hz; RG, 0.7 Hz; Pl, 1 Hz). Muscle citrate and acetyl-CoA were elevated in Sol during several stimulation protocols with high FFA, but this effect was inconsistent in Pl and RG. The sparing of glycogen, when it did occur, was generally unrelated to increases in either citrate or acetyl-CoA content. Furthermore, protocols in which citrate or acetyl-CoA were elevated in the presence of elevated FFA did not demonstrate glycogen sparing. Hindlimb lactate efflux at rest was reduced with FFA but unaffected during stimulation. Glucose uptake was unaffected by FFA at rest and during stimulation protocols, except 3 Hz. The present study does not support the classically proposed roles of citrate and acetyl-CoA in the FFA-induced downregulation of CHO utilization in electrically stimulated rat skeletal muscle.

In vitro studies on the effect of glucocorticoids on the metabolism of perfused rat skeletal muscle

1984 ◽  
Vol 104 (4_Supplb) ◽  
pp. S110-S111
Author(s):  
P. SCHADEWALDT ◽  
H. MEYER
Keyword(s):  
Skeletal Muscle ◽  
In Vitro Studies ◽  
Rat Skeletal Muscle

Proton leak induced by reactive oxygen species produced during in vitro anoxia/reoxygenation in rat skeletal muscle mitochondria

2006 ◽  
Vol 38 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Rachel Navet ◽  
Ange Mouithys-Mickalad ◽  
Pierre Douette ◽  
Claudine M. Sluse-Goffart ◽  
Wieslawa Jarmuszkiewicz ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Skeletal Muscle ◽  
Reactive Oxygen ◽  
Proton Leak ◽  
Oxygen Species ◽  
Rat Skeletal Muscle ◽  
Muscle Mitochondria ◽  
Skeletal Muscle Mitochondria

scholarly journals Reversible ATP-induced inactivation of branched-chain 2-oxo acid dehydrogenase

1980 ◽  
Vol 192 (1) ◽  
pp. 155-163 ◽  
Author(s):  
R Odessey
Keyword(s):  
Skeletal Muscle ◽  
Liver Mitochondria ◽  
Initial Activity ◽  
Rat Skeletal Muscle ◽  
Kidney Mitochondria ◽  
Physiological Conditions ◽  
Acid Dehydrogenase ◽  
Skeletal Muscle Mitochondria ◽  
Branched Chain

The branched chain 2-oxo acid dehydrogenase from rat skeletal muscle, heart, kidney and liver mitochondria can undergo a reversible activation-inactivation cycle in vitro. Similar results were obtained with the enzyme from kidney mitochondria of pig and cow. The dehydrogenase is markedly inhibited by ATP and the inhibition is not reversed by removing the nucleotide. The non-metabolizable ATP analogue adenosine 5′-[beta gamma-imido] triphosphate can block the effect of ATP when added with the nucleotide, but has no effect by itself, nor can it reverse the inhibition in mitochondria preincubated with ATP. These findings suggest that the branched chain 2-oxo acid dehydrogenase undergoes a stable modification that requires the splitting of the ATP gamma-phosphate group. In skeletal muscle mitochondria the rate of inhibition by ATP is decreased by oxo acid substrates and enhanced by NADH. The dehydrogenase can be reactivated 10-20 fold by incubation at pH 7.8 in a buffer containing Mg2+ and cofactors. Reactivation is blocked by NaF (25 mM). The initial activity of dehydrogenase extracted from various tissues of fed rats varies considerably. Activity is near maximal in kidney and liver whereas the dehydrogenase in heart and skeletal muscle is almost completely inactivated. These studies emphasize that comparisons of branched chain 2-oxo acid dehydrogenase activity under various physiological conditions or in different tissues must take into account its state of activation. Thus the possibility exists that the branched chain 2-oxo acid dehydrogenase may be physiologically regulated via a covalent mechanism.

Properties of 5′-deiodinase of 3,3′,5′-triiodothyronine in rat skeletal muscle

1989 ◽  
Vol 120 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Fujiko Tsukahara ◽  
Teruko Nomoto ◽  
Michiko Maeda
Keyword(s):  
Skeletal Muscle ◽  
Drinking Water ◽  
Incubation Medium ◽  
Marked Reduction ◽  
Daily Administration ◽  
Type I ◽  
Rat Skeletal Muscle ◽  
Thyroid Status ◽  
Altered Thyroid

Abstract. To characterize rT3 5′-deiodinase (5′D) in rat skeletal muscle, the effects of altered thyroid status and PTU on rT3 5′D were studied. rT3 5′D activity was measured by incubating homogenates of rat skeletal muscle with [125]rT3, iodine labelled in the outer ring, in the presence of 20 mmol/l DL-dithiothreitol. This activity was observed to increase significantly 24 h after a single sc injection of T3 (75 μg/kg). The increase following the daily administration of this drug (15 or 75 μg/kg) for 3 and 14 days was dependent on the dose and number of previous days of injection. A significant decrease in activity was observed 2 weeks after thyroidectomy. The addition of 0.1 mmol/l 6-n-propyl-2-thiouracil (PTU) to the incubation medium in vitro caused a marked reduction in the activity in homogenates of skeletal muscle from hypothyroid, euthyroid and hyperthyroid rats. PTU, present at 0.05% in the drinking water for 2 weeks virtually abolished it. The properties of rT3 5′D in rat skeletal muscle thus appear to be essentially the same as those of type I enzyme with respect to response toward altered thyroid status and PTU.

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