scholarly journals Relationships between carnitine and coenzyme A esters in tissues of normal and alloxan-diabetic sheep

1972 ◽  
Vol 127 (1) ◽  
pp. 133-141 ◽  
Author(s):  
A. M. Snoswell ◽  
Patricia P. Koundakjian
Keyword(s):  
Skeletal Muscle ◽  
Alloxan Diabetes ◽  
Biceps Femoris ◽  
Kidney Cortex ◽  
Carnitine Acetyltransferase ◽  
Total Acid ◽  
Acetyl Coa ◽  
Adult Sheep ◽  
Ruminant Metabolism

1. The total acid-soluble carnitine concentrations of four tissues from Merino sheep showed a wide variation not reported for other species. The concentrations were 134, 538, 3510 and 12900nmol/g wet wt. for liver, kidney cortex, heart and skeletal muscle (M. biceps femoris) respectively. 2. The concentration of acetyl-CoA was approximately equal to the concentration of free CoA in all four tissues and the concentration of acid-soluble CoA (free CoA plus acetyl-CoA) decreased in the order liver>kidney cortex>heart>skeletal muscle. 3. The total amount of acid-soluble carnitine in skeletal muscle of lambs was 40% of that in the adult sheep, whereas the concentration of acid-soluble CoA was 2.5 times as much. A similar inverse relationship between carnitine and CoA concentrations was observed when different muscles in the adult sheep were compared. 4. Carnitine was confined to the cytosol in all four tissues examined, whereas CoA was equally distributed between the mitochondria and cytosol in liver, approx. 25% was present in the cytosol in kidney cortex and virtually none in this fraction in heart and skeletal muscle. 5. Carnitine acetyltransferase (EC 2.3.1.7) was confined to the mitochondria in all four tissues and at least 90% of the activity was latent. 6. Acetate thiokinase (EC 6.2.1.1) was predominantly (90%) present in the cytosol in liver, but less than 10% was present in this fraction in heart and skeletal muscle. 7. In alloxan-diabetes, the concentration of acetylcarnitine was increased in all four tissues examined, but the total acid-soluble carnitine concentration was increased sevenfold in the liver and twofold in kidney cortex. 8. The concentration of acetyl-CoA was approximately equal to that of free CoA in the four tissues of the alloxan diabetic sheep, but the concentration of acid-soluble CoA in liver increased approximately twofold in alloxan-diabetes. 9. The relationship between CoA and carnitine and the role of carnitine acetyltransferase in the various tissues is discussed. The quantitative importance of carnitine in ruminant metabolism is also emphasized.

scholarly journals The Liver as the Site of Carnitine Biosynthesis in Sheep with Alloxan-induced Diabetes

1974 ◽  
Vol 27 (6) ◽  
pp. 645 ◽  
Author(s):  
AM Snoswell ◽  
GH Mclntosh
Keyword(s):  
Skeletal Muscle ◽  
Biceps Femoris ◽  
Kidney Cortex ◽  
Total Acid ◽  
Diabetic State ◽  
Threefold Increase ◽  
Wet Weight ◽  
Significant Change ◽  
Total Carnitine ◽  
Carnitine Concentration

The total acid-soluble carnitine concentration in the livers of three sheep increased 20-fold, to 4530 nmoljg wet weight, 10-14 days after induction of the diabetic state by alloxan. There was a threefold increase in the total carnitine concentration of the kidney cortex and no significant change in that of heart or skeletal muscle (M. biceps femoris).

Carnitine secretion into milk of ruminants

1975 ◽  
Vol 42 (3) ◽  
pp. 371-380 ◽  
Author(s):  
A. M. Snoswell ◽  
J. L. Linzell
Keyword(s):  
Mammary Tissue ◽  
Kidney Cortex ◽  
Long Chain Fatty Acids ◽  
Carnitine Acetyltransferase ◽  
Total Acid ◽  
Blood Flows ◽  
Arterial Blood ◽  
Ewe's Milk ◽  
Membrane Bound ◽  
Carnitine Concentration

SummaryTotal acid-soluble carnitine concentration in cow's, goat's and ewe's milk was 117, 101 and 872 nmol/ml respectively, of which acetylcarnitine made up 30% in goats, 10% in cows and 11% in ewes. The concentration of carnitine in the arterial blood of goats decreased significantly (P < 0·01) with the onset of lactation from 18·1 to 8·4nmol/ml and during lactation in goats and cows there was a significant arterio-venous difference of carnitine across the udder, with mean extractions of 14 and 5% respectively. Calculation of the udder uptake of carnitine, from these figures and from udder blood-flows, showed that in goats the amount lost in the milk was much less than that taken from the blood, but in cows about the same. Two groups of lactating ewes on low and high nutritional planes were sampled at 2-weekly intervals from 2 to 8 weeks of lactation. The concentrations of total acid-soluble carnitine and acetylcarnitine in the milk were similar in the 2 groups and remained relatively constant over this period, but the total acid-soluble carnitine concentration in jugular blood from the ewes on the low nutritional plane was significantly (P < 0·01) higher than from the ewes on the higher nutritional plane from the fourth week of lactation. The total acid-soluble carnitine concentration in liver of goats was 290 nmol/g wet wt; mammary gland, 324; kidney-cortex, 692; heart, 2030 and skeletal muscle, 14300. Carnitine acetyltransferase (E.C. 2.3.1.7) activity of mammary tissue from lactating ewes was 0·6 μmol per min per g wet wt of which approximately half appeared to be ‘latent’ or membrane bound. Acetate thiokinase (E.C. 6.2.1.1) activity in this tissue was found to be 1·5 μmol per min per g wet wt and was predominantly localized in the cytoplasm. Carnitine palmitoyltransferase (E.C. 2.3.1.21) activity in the same tissue was 0·8 μmol per min per g wet wt while no acetylcarnitine hydrolase activity could be detected. The results suggest that carnitine in mammary tissue is extracted from the blood for the oxidation of both acetate and long-chain fatty acids and that some is lost in the milk.

scholarly journals A Survey of Methionine Adenosyltransferase and Cystathionine "g-Lyase Activities in Ruminant Tissues

1974 ◽  
Vol 27 (5) ◽  
pp. 465 ◽  
Author(s):  
BC Radcliffe ◽  
AR Egan
Keyword(s):  
Skeletal Muscle ◽  
Methionine Adenosyltransferase ◽  
Kidney Cortex ◽  
Duodenal Wall ◽  
Kidney Medulla ◽  
Key Enzymes ◽  
Adult Sheep ◽  
Adult Rat

The activities of two key enzymes, methionine adenosyltransferase (EC 2.5.1.6) and cystathionine y-lyase (EC 4.4.1.1), involved in the metabolism of methionine to cyst(e)ine have been studied in the liver, heart, kidney medulla, kidney cortex, pancreas, duodenal wall, spleen and skeletal muscle in the neonatallarnb, unweaned lamb, adult sheep, pre-ruminant calf, ruminant steer and adult goat, and for comparative purposes in the adult rat.

scholarly journals Production and utilization of acetate in mammals

1974 ◽  
Vol 142 (2) ◽  
pp. 401-411 ◽  
Author(s):  
Spencer E. Knowles ◽  
Ivan G. Jarrett ◽  
Owen H. Filsell ◽  
F. John Ballard
Keyword(s):  
Alloxan Diabetes ◽  
Ketone Bodies ◽  
Tricarboxylic Acid Cycle ◽  
Mitochondrial Fraction ◽  
The Body ◽  
Kidney Cortex ◽  
Synthetase Activity ◽  
Acetyl Coa ◽  
Mitochondrial Fractions ◽  
Coa Hydrolase

1. In an attempt to define the importance of acetate as a metabolic precursor, the activities of acetyl-CoA synthetase (EC 6.2.1.1) and acetyl-CoA hydrolase (Ec 3.1.2.1) were assayed in tissues from rats and sheep. In addition, the concentrations of acetate in blood and liver were measured, as well as the rates of acetate production by tissue slices and mitochondrial fractions of these tissues. 2. Acetyl-CoA synthetase occurs at high activities in heart and kidney cortex of both species as well as in rat liver and the sheep masseter muscle. The enzyme is mostly in the cytosol fraction of liver, whereas it is associated with the mitochondrial fraction in heart tissue. Both mitochondrial and cytosol activities have a Km for acetate of 0.3mm. Acetyl-CoA synthetase activity in liver was not altered by changes in diet, age or alloxan-diabetes. 3. Acetyl-CoA hydrolase is widely distributed in rat and sheep tissues, the highest activity being found in liver. Essentially all of the activity in liver and heart is localized in the mitochondrial fraction. Hepatic acetyl-CoA hydrolase activity is increased by starvation in rats and sheep and during the suckling period in young rats. 4. The concentrations of acetate in blood are decreased by starvation and increased by alloxan-diabetes in both species. The uptake of acetate by the sheep hind limb is proportional to the arterial concentration of acetate, except in alloxan-treated animals, where uptake is impaired. 5. Acetate is produced by liver and heart slices and also by heart mitochondrial fractions that are incubated with either pyruvate or palmitoyl-(—)-carnitine. Liver mitochondrial fractions do not form acetate from either substrate but instead convert acetate into acetoacetate. 6. We propose that acetate in the blood of rats or starved sheep is derived from the hydrolysis of acetyl-CoA. Release of acetate from tissues would occur under conditions when the function of the tricarboxylic acid cycle is restricted, so that the circulating acetate serves to redistribute oxidizable substrate throughout the body. This function is analogous to that served by ketone bodies.

Changes in NO bioavailabilty regulate cardiac O2 consumption: control by intramitochondrial SOD2 and intracellular myoglobin

2004 ◽  
Vol 286 (1) ◽  
pp. H47-H54 ◽  
Author(s):  
Wei Li ◽  
Thomas Jue ◽  
John Edwards ◽  
Xipping Wang ◽  
Thomas H. Hintze
Keyword(s):  
Skeletal Muscle ◽  
Negative Control ◽  
Kidney Cortex ◽  
Mouse Heart ◽  
Wild Type ◽  
Mitochondrial Superoxide ◽  
No Bioavailability ◽  
Consumption Control

The aim of this study was to investigate the significance of two intracellular scavengers of nitric oxide (NO): 1) superoxide dismutase (SOD) (SOD2) to scavenge intramitochondrial superoxide anion, and 2) cytosolic myoglobin (Mb) in the regulation of tissue O2 consumption. O2 consumption was measured in vitro using a Clark-type O2 electrode. SOD heterozygous mice (SODHZ) ( n = 13) and SOD wild-type (SODWT) ( n = 5) mice were used. Bradykinin (BK, 10–4 mol/l) reduced O2 consumption by 15% ± 1 in hearts of SODHZ mice, which was significantly different from SODWT (reduced by 24 ± 0.4%). Tiron significantly increased the inhibition of O2 consumption by BK in male mice from 15 ± 1% ( n = 13) to 29 ± 1.2% ( n = 4) at 10–4 mol/l concentration ( P < 0.05). The effect of carbachol was similar to BK. S-nitroso- N-acetyl penicillamine (SNAP, 10–4 mol/l) reduced O2 consumption by 39 ± 1.3% in hearts of SODHZ mice, which was not significantly different from SODWT. But at 10–7 mol/l, SNAP caused significantly less inhibition of O2 consumption in SODHZ mice. Mb knockout (MbKO; Mb wild-type n = 6) and (MbWT) mice ( n = 6) were also used. Kidney cortex was studied as the negative control because it does not contain Mb. BK (10–4 mol/l) reduced O2 consumption by 32 ± 2, 29 ± 1, and 26 ± 1% in the heart, skeletal muscle, and kidney of MbKO mice, which was also not significantly different from MbWT. SNAP (10–4 mol/l) reduced O2 consumption by 39 ± 3, 42 ± 4, and 46 ± 2% in the heart, skeletal muscle, and kidney of MbKO mice, which was also not significantly different from MbWT. NG-nitro-l-arginine methyl ester ( P < 0.05) inhibited the reduction in O2 consumption induced by BK in the MbKO mouse heart (15 ± 1%), skeletal muscle (17 ± 1%), and kidney (17 ± 1%) as in the MbWT mice. These results suggest that the role of Mb as an intracellular NO scavenger is small, and the increase in mitochondrial superoxide in SODHZ mice may cause a decrease NO bioavailability and alter the control of myocardial O2 consumption by NO.

The role of rice bran extract on acetyl CoA carboxylase in liver of rats fed a high-fat diet

Planta Medica ◽  
2011 ◽  
Vol 77 (12) ◽  
Author(s):  
C Charkhonpunya ◽  
S Sireeratawong ◽  
S Komindr ◽  
N Lerdvuthisopon
Keyword(s):  
Rice Bran ◽  
High Fat Diet ◽  
Acetyl Coa Carboxylase ◽  
High Fat ◽  
Acetyl Coa ◽  
Rice Bran Extract

MIOPATIA MUSCULAR ESQUELÉTICA INDUZIDA PELA INSUFICIÊNCIA CARDÍACA DE ETIOLOGIA HIPERTENSIVA: PAPEL TERAPÊUTICO DO TREINAMENTO FÍSICO AERÓBIOHYPERTENSIVE HEART FAILURE-INDUCED SKELETAL MUSCLE MYOPATHY: THERAPEUTIC ROLE OF AEROBIC EXERCISE TRAININGRESUMOA insuficiência cardíaca (IC) é a via final comum da maioria das doenças que acometem o coração. Entre os fatores de risco conhecidos, a hipertensão arterial (HA) é a doença mais frequentemente associada à IC. Caracterizada pela intolerância ao exercício, a IC promove disfunção cardíaca e alterações intrínsecas musculares envolvidas na redução da capacidade física. Várias anormalidades do músculo esquelético têm sido descritas em pacientes e animais com IC, incluindo atrofia, fibrose, mudança na composição dos tipos de fibras, rarefação microvascular e reduzida capacidade de oxidação. Por outro lado, o treinamento físico aeróbio (TFA) vem sendo utilizado como uma importante terapia não farmacológica para a prevenção e o tratamento da IC; em parte, por melhorar a função endotelial e a perfusão coronária, diminuir a resistência vascular periférica e induzir o remodelamento das células musculares cardíacas e esqueléticas, levando ao aumento da captação de oxigênio e resistência à fadiga. Os mecanismos e vias de sinalização intracelular envolvidas nas anormali

2020 ◽  
Vol 30 (2) ◽  
pp. 239-247
Author(s):  
Bruno Rocha de Avila Pelozin ◽  
◽  
Larissa Ferreira-Santos ◽  
Luis Felipe Rodrigues ◽  
Edilamar Menezes de Oliveira ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Aerobic Exercise ◽  
Therapeutic Role ◽  
Insuficiencia Cardiaca
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