scholarly journals The effect of ketone bodies on alanine and glutamine metabolism in isolated skeletal muscle from the fasted chick

1988 ◽  
Vol 255 (1) ◽  
pp. 139-144 ◽  
Author(s):  
G Y Wu ◽  
J R Thompson
Keyword(s):  
Ketone Bodies ◽  
Intracellular Concentration ◽  
Glutamine Metabolism ◽  
Inhibiting Effect ◽  
Branched Chain Amino Acid ◽  
The Media ◽  
Inhibition Of Glycolysis ◽  
Alanine Synthesis ◽  
Branched Chain ◽  
Beta Hydroxybutyrate

The effects of ketone bodies on the metabolism of alanine and glutamine were studied in isolated extensor digitorum communis (EDC) muscles from 24 h-fasted chicks. (1) Acetoacetate and DL-beta-hydroxybutyrate (4 mM) markedly inhibit branched-chain amino acid (BCAA) transamination and alanine formation. (2) Ketone bodies (1 and 4 mM) increase the intracellular concentration and release of glutamate and glutamine, suggesting that inhibition of BCAA transamination does not limit intracellular availability of glutamate for alanine synthesis. (3) Ketone bodies (1 and 4 mM) do not affect glucose uptake by muscles, but decrease the rate of glycolysis as well as the intracellular concentration and release of pyruvate in muscles. (4) Addition of 12 mM-glucose increases the formation of alanine in muscles incubated in the absence of ketone bodies, but has no effect in muscles incubated in the presence of 4 mM ketone bodies. (5) Addition of 5 mM-pyruvate to the media prevents the inhibiting effect of ketone bodies on BCAA transamination and alanine synthesis. These results suggest that ketone bodies decrease alanine synthesis by limiting the intracellular availability of pyruvate, owing to inhibition of glycolysis, and inhibit BCAA transamination by decreasing the intracellular concentration of amino-group acceptors such as pyruvate in EDC muscles from fasted chicks.

scholarly journals NMR-Based Metabonomic Study Reveals Intervention Effects of Polydatin on Potassium Oxonate-Induced Hyperuricemia in Rats

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Bin Han ◽  
Mengjuan Gong ◽  
Zhong Li ◽  
Yuqin Qiu ◽  
Zhongjie Zou
Keyword(s):  
Ketone Bodies ◽  
Tricarboxylic Acid Cycle ◽  
Therapeutic Effects ◽  
Holistic View ◽  
Branched Chain Amino Acid ◽  
Metabolic Mechanism ◽  
Branched Chain ◽  
Underlying Mechanisms ◽  
Natural Precursor ◽  
Potassium Oxonate

Previous studies have disclosed the antihyperuricemic effect of polydatin, a natural precursor of resveratrol; however, the mechanisms of action still remain elusive. The present study was undertaken to evaluate the therapeutic effects and the underlying mechanisms of polydatin on potassium oxonate-induced hyperuricemia in rats through metabonomic technology from a holistic view. Nuclear magnetic resonance (NMR) spectroscopy was applied to capture the metabolic changes in sera and urine collected from rats induced by hyperuricemia and polydatin treatment. With multivariate data analysis, significant metabolic perturbations were observed in hyperuricemic rats compared with the healthy controls. A total of eleven and six metabolites were identified as differential metabolites related to hyperuricemia in serum and urine of rats, respectively. The proposed pathways primarily included branched-chain amino acid (BCAA) metabolism, glycolysis, the tricarboxylic acid cycle, synthesis and degradation of ketone bodies, purine metabolism, and intestinal microflora metabolism. Additionally, some metabolites indicated the risk of renal injury induced by hyperuricemia. Polydatin significantly lowered the levels of serum uric acid, creatinine, and blood urea nitrogen and alleviated the abnormal metabolic status in hyperuricemic rats by partially restoring the balance of the perturbed metabolic pathways. Our findings shed light on the understanding of the pathophysiological process of hyperuricemia and provided a reference for revealing the metabolic mechanism produced by polydatin in the treatment of hyperuricemia.

scholarly journals Palmitate inhibits liver glycolysis. Involvement of fructose 2,6-bisphosphate in the glucose/fatty acid cycle

1988 ◽  
Vol 251 (2) ◽  
pp. 541-545 ◽  
Author(s):  
L Hue ◽  
L Maisin ◽  
M H Rider
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Ketone Bodies ◽  
Acid Cycle ◽  
Glucose Fatty Acid Cycle ◽  
Inhibition Of Glycolysis ◽  
Beta Hydroxybutyrate ◽  
Fasted Rats

In hepatocytes from overnight-fasted rats incubated with glucose, palmitate decreased the production of lactate, the detritiation of [2-3H]- and [3-3H]-glucose, and the concentration of fructose 2,6-bisphosphate. Similarly, perfusion of hearts from fed rats with beta-hydroxybutyrate resulted in an inhibition of the detritiation of [3-3H]glucose and a fall in fructose 2,6-bisphosphate concentration. This fall could result from an increase in citrate (hepatocytes and heart) and sn-glycerol 3-bisphosphate concentration. It is suggested that a fall in fructose 2,6-bisphosphate concentration participates in the inhibition of glycolysis by fatty acids and ketone bodies.

scholarly journals Branched-chain amino acid metabolism and alanine formation in rat muscles in vitro. Mitochondrial-cytosolic interrelationships

1985 ◽  
Vol 225 (3) ◽  
pp. 737-743 ◽  
Author(s):  
K Snell ◽  
D A Duff
Keyword(s):  
Amino Acid ◽  
Aspartate Aminotransferase ◽  
Alanine Aminotransferase ◽  
Amino Acid Metabolism ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Acid Metabolism ◽  
Branched Chain Amino Acid ◽  
Alanine Synthesis ◽  
Branched Chain ◽  
Branched Chain Aminotransferase

Muscle branched-chain amino acid metabolism is coupled to alanine formation via branched-chain amino acid aminotransferase and alanine aminotransferase, but the subcellular distributions of these and other associated enzymes are uncertain. Recovery of branched-chain aminotransferase in the cytosol fraction after differential centrifugation was shown to be accompanied by leakage of mitochondrial-matrix marker enzymes. By using a differential fractional extraction procedure, most of the branched-chain aminotransferase activity in rat muscle was located in the mitochondrial compartment, whereas alanine aminotransferase was predominantly in the cytosolic compartment. Phosphoenolpyruvate carboxykinase, like aspartate aminotransferase, was approximately equally distributed between these subcellular compartments. This arrangement necessitates a transfer of branched-chain amino nitrogen and carbon from the mitochondria to the cytosol for alanine synthesis de novo to occur. In incubations of hemidiaphragms from 48 h-starved rats with 3mM-valine or 3mM-glutamate, the stimulation of alanine release was inhibited by 69% by 1 mM-aminomethoxybut-3-enoate, a selective inhibitor of aspartate aminotransferase. Leucine-stimulated alanine release was unaffected. These data implicate aspartate aminotransferase in the transfer of amino acid carbon and nitrogen from the mitochondria to the cytosol, and suggest that oxaloacetate, via phosphoenolpyruvate carboxykinase, can serve as an intermediate on the route of pyruvate formation for muscle alanine synthesis.

Plasma amino acid kinetics during acute states of glucagon deficiency and excess in healthy adults

1990 ◽  
Vol 258 (1) ◽  
pp. E78-E85 ◽  
Author(s):  
C. Couet ◽  
N. K. Fukagawa ◽  
D. E. Matthews ◽  
D. M. Bier ◽  
V. R. Young
Keyword(s):  
Amino Acid ◽  
De Novo ◽  
Healthy Young Adult ◽  
Peripheral Tissues ◽  
Adult Men ◽  
Branched Chain Amino Acid ◽  
Alanine Synthesis ◽  
Plasma Hormone ◽  
Branched Chain ◽  
Plasma Leucine

The effects of glucagon deficiency and excess on plasma leucine, lysine, and alanine were examined in six healthy young adult men, with primed continuous infusions of L-[1-13C]- or L-[5,5,5-2H3]leucine, L-[alpha-15N]-lysine, and L-[3-13C]alanine for 150 min before and during 210 min of either a glucagon-deficient euglycemic state (experiment 1), a basal glucagon state (experiment 2), or a glucagon-excess state (experiment 3). Steady-state plasma hormone levels were achieved by infusion of somatostatin (250 micrograms/h) and insulin (0.07 mU.kg-1.min-1), without (experiment 1) or with an infusion of glucagon at 0.7 ng.kg-1.min-1 (experiment 2) or 2.5 ng.kg-1.min-1 (experiment 3). Plasma branched-chain amino acid (AA) concentrations did not change with altered glucagon status, whereas significant differences were observed for plasma lysine, alanine, glycine, serine, threonine, proline, tyrosine, citrulline, and ornithine levels (0.05 greater than P greater than 0.001). Plasma leucine, lysine, and alanine fluxes and the rate of de novo alanine synthesis showed no significant changes with either glucagon deficiency or excess. These findings lead to the conclusion that glucagon-induced alterations in plasma AA profiles are not due to changes in the rate of appearance of AA from peripheral tissues but rather a consequence of changes in the fate of AA within the splanchnic region.

Fetal fuels. IV. Regulation of branched-chain amino and keto acid metabolism in fetal brain

1981 ◽  
Vol 241 (3) ◽  
pp. E200-E207
Author(s):  
G. E. Shambaugh ◽  
R. A. Koehler
Keyword(s):  
Acid Metabolism ◽  
Ketone Bodies ◽  
Brain Slices ◽  
Fetal Brain ◽  
Keto Acid ◽  
Inhibitory Effects ◽  
Fetal Rat ◽  
Keto Acids ◽  
Branched Chain ◽  
Beta Hydroxybutyrate

The regulation of branched-chain amino and keto acid metabolism was examined in fetal rat brains at 20 days gestation. When fetal brain slices were incubated with [1-14C]leucine, graded concentrations of beta-hydroxybutyrate or acetoacetate resulted in a progressive rise in labeled alpha-ketoisocaproic acid accompanied by a fall in 14CO2, whereas the sum of these products remained unchanged. These reciprocal relationships were maintained when leucine concentrations were varied from 0.4 to 4 mM. Increasing concentrations of glucose or pyruvate enhanced the formation of both 14CO2 and alpha-ketoisocaproic acid from [1–14C]leucine, but resulted in a progressive decrease in the conversion of alpha-ketoisocaproic acid to 14CO2. That glucose and ketone bodies probably acted via separate mechanisms was suggested by a further inhibition of alpha-ketoisocaproic acid decarboxylation whenever beta-hydroxybutyrate was added. When mothers were starved from days 18–20, a threefold rise in circulating branched-chain keto acids was reflected concordantly in the fetus and was attended by a significant enhancement of leucine transaminase activity in fetal brain. Because levels of circulating ketone bodies reported during maternal starvation were maximally effective in diminishing the conversion of alpha-ketoisocaproic acid to 14CO4, it is suggested that the inhibitory effects of beta-hydroxybutyrate on the critical dehydrogenase step in branched-chain keto acid metabolism in fetal brain could restrain oxidation of maternally derived alpha-ketoisocaproic acid, thereby permitting salvage for reversible transamination to leucine.

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