PATHWAYS OF CARBOHYDRATE METABOLISM IN LOBSTER HEPATOPANCREAS

1962 ◽  
Vol 40 (8) ◽  
pp. 1043-1050 ◽  
Author(s):  
P. W. Hochachka ◽  
J. M. Teal ◽  
M. Telford
Keyword(s):  
Citric Acid ◽  
Oxygen Uptake ◽  
Carbohydrate Metabolism ◽  
Citric Acid Cycle ◽  
The Other ◽  
Short Term ◽  
Acid Cycle

Oxygen uptake by homogenates of lobster hepatopancreas was stimulated by the addition of Embden–Meyerhof, pentose cycle, and citric acid cycle intermediates as well as xylose. Acetate-1-C14oxidation was blocked by fluoracetate and glucose-1-C14oxidation fell by 80% with iodoacetate treatment. TPN and DPN increased glucose-1-C14oxidation by 140% and 20% and acetate-1-C14oxidation by 50% and 100% respectively. Large amounts of C14enter polysaccharide following treatment with glucose-1-C14or acetate-1-C14but very little enters after treatment with the same amount of gluconate-1-C14. Gluconate and xylose oxidation occurs in mitochondria-free preparations. In short-term tests with acetate-1-C14as substrate, most of the label in glycogen is on carbons 3 and 4 and the amount in the other positions can be explained on the basis of a 5–10% participation of the pentose cycle.

PATHWAYS OF CARBOHYDRATE METABOLISM IN LOBSTER HEPATOPANCREAS

1962 ◽  
Vol 40 (1) ◽  
pp. 1043-1050 ◽  
Author(s):  
P. W. Hochachka ◽  
J. M. Teal ◽  
M. Telford
Keyword(s):  
Citric Acid ◽  
Oxygen Uptake ◽  
Carbohydrate Metabolism ◽  
Citric Acid Cycle ◽  
The Other ◽  
Short Term ◽  
Acid Cycle

Oxygen uptake by homogenates of lobster hepatopancreas was stimulated by the addition of Embden–Meyerhof, pentose cycle, and citric acid cycle intermediates as well as xylose. Acetate-1-C14oxidation was blocked by fluoracetate and glucose-1-C14oxidation fell by 80% with iodoacetate treatment. TPN and DPN increased glucose-1-C14oxidation by 140% and 20% and acetate-1-C14oxidation by 50% and 100% respectively. Large amounts of C14enter polysaccharide following treatment with glucose-1-C14or acetate-1-C14but very little enters after treatment with the same amount of gluconate-1-C14. Gluconate and xylose oxidation occurs in mitochondria-free preparations. In short-term tests with acetate-1-C14as substrate, most of the label in glycogen is on carbons 3 and 4 and the amount in the other positions can be explained on the basis of a 5–10% participation of the pentose cycle.

scholarly journals Citrus Flavanones Affect Hepatic Fatty Acid Oxidation in Rats by Acting as Prooxidant Agents

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Rodrigo Polimeni Constantin ◽  
Gilson Soares do Nascimento ◽  
Renato Polimeni Constantin ◽  
Clairce Luzia Salgueiro ◽  
Adelar Bracht ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Citric Acid ◽  
Oxygen Uptake ◽  
Fatty Acid Oxidation ◽  
Citric Acid Cycle ◽  
Acid Oxidation ◽  
Acid Cycle ◽  
Hepatic Fatty Acid ◽  
Wide Range ◽  
Hepatic Fatty Acid Oxidation

Citrus flavonoids have a wide range of biological activities and positive health effects on mammalian cells because of their antioxidant properties. However, they also act as prooxidants and thus may interfere with metabolic pathways. The purpose of this work was to evaluate the effects of three citrus flavanones, hesperidin, hesperetin, and naringenin, on several parameters linked to fatty acid oxidation in mitochondria, peroxisomes, and perfused livers of rats. When exogenous octanoate was used as substrate, hesperetin and naringenin reduced the mitochondrial NADH/NAD+ratio and stimulated the citric acid cycle without significant changes on oxygen uptake or ketogenesis. When fatty acid oxidation from endogenous sources was evaluated, hesperetin and naringenin strongly reduced the mitochondrial NADH/NAD+ratio. They also inhibited both oxygen uptake and ketogenesis and stimulated the citric acid cycle. Hesperidin, on the other hand, had little to no effect on these parameters. These results confirm the hypothesis that citrus flavanones are able to induce a more oxidised state in liver cells, altering parameters related to hepatic fatty acid oxidation. The prooxidant effect is most likely a consequence of the ability of these substances to oxidise NADH upon production of phenoxyl radicals in the presence of peroxidases and hydrogen peroxide.

scholarly journals Metabolism of Semen After Freezing [[ . The Aerobic Metabolism of Ram Spermatozoa Before and After Storage at ?79°C

1969 ◽  
Vol 22 (3) ◽  
pp. 733
Author(s):  
T O'shea
Keyword(s):  
Citric Acid ◽  
Oxygen Uptake ◽  
Sodium Acetate ◽  
Citric Acid Cycle ◽  
Cell Metabolism ◽  
Sodium Lactate ◽  
Aerobic Metabolism ◽  
Sodium Salts ◽  
Acid Cycle ◽  
Before And After

The metabolism of ram spermatozoa, incubated at 37�0 shortly after ejacula-tion and after storage overnight at -79�0, was examined using various combinations of fructose, sodium lactate, sodium acetate, and sodium salts of citric acid cycle intermediates. Although freezing depressed all indices of cell metabolism, there were few qualitative differences between the metabolism by fresh or thawed semen of the various substrates. The increased oxygen uptake of thawed spermatozoa on addition of succinate was unrelated to motility and to other parameters of metabolism.

Studies in relation to biosynthesis. XLI. Canescin

1969 ◽  
Vol 22 (11) ◽  
pp. 2429 ◽  
Author(s):  
AJ Birch ◽  
F Gager ◽  
L Mo ◽  
A Pelter ◽  
JJ Wright
Keyword(s):  
Citric Acid ◽  
Carbon Atom ◽  
Citric Acid Cycle ◽  
Lactone Ring ◽  
Carbon Chain ◽  
The Other ◽  
Methoxyl Group ◽  
Acid Cycle ◽  
Polyketide Chain

The biosynthesis of canescin (I) has been investigated. The isocoumarin portion is derived from a polyketide chain. One carbon atom of the γ- lactone ring and the carbon atom of the methoxyl group originate from methionine whilst the other three carbon atoms of the γ-lactone have a symmetrical C4-acid of the citric acid cycle as their precursor. This metabolite is most unusual in that an oxygenated methionine-derived carbon atom provides the growing point of a new carbon chain. A possible mechanism for the attachment of the lactone is suggested.

THE NUTRITION OF VIBRIO COSTICOLUS: II. CYST(E)INE UTILIZATION

1964 ◽  
Vol 10 (2) ◽  
pp. 235-242
Author(s):  
W. L. Flannery ◽  
S. N. Durio
Keyword(s):  
Sodium Chloride ◽  
Citric Acid ◽  
Oxygen Uptake ◽  
Hydrogen Sulphide ◽  
Pyruvic Acid ◽  
Citric Acid Cycle ◽  
Chloride Concentration ◽  
Sodium Chloride Concentration ◽  
Acid Cycle ◽  
Essential Nutrient

The effect of cyst(e)ine and sodium chloride concentration on oxygen uptake, and hydrogen sulphide, ammonia, and pyruvic acid production by Vibrio costicolus is described. Added pyridoxal was unnecessary for maximum desulphydrase activity. Generally, oxidation curves of cyst(e)ine concentrations 4 μM or less were the customary type whereas curves which resulted from the oxidation of 6.25 μM cyst(e}ine and greater were of a type indicating accumulation of a product toxic to the system. This occurred in the presence of 1 M NaCl and the suppressed type of oxidation could be returned to normal by increasing the concentration of NaCl. Pyruvic acid accumulated in the flasks showing the suppressed type of oxidation curves, but did not accumulate in flasks showing customary oxidation curves. Pyruvic acid did not accumulate in flasks containing 6.25 μM cyst(e)ine if the sodium chloride concentration was increased to 1.5 M or greater. Pyruvic acid did accumulate with 3.125 μM cyst(e)ine if a citric acid cycle inhibitor (sodium fluoroacetate) was added to the flask contents. These studies suggest that the most likely pathway for the utilization of cyst(e)ine, an essential nutrient for V. costicolus, is its conversion to pyruvate to enter the citric acid cycle.

Citric acid cycle in certain alterations of acid-base balance in human subjects

1961 ◽  
Vol 16 (4) ◽  
pp. 593-596 ◽  
Author(s):  
Wilbert Gamble ◽  
James M. Orten ◽  
Arthur H. Smith
Keyword(s):  
Citric Acid ◽  
Urinary Excretion ◽  
Citric Acid Cycle ◽  
Human Subjects ◽  
Statistical Significance ◽  
The Other ◽  
Acid Base Balance ◽  
Acid Base ◽  
Acid Cycle ◽  
Base Balance

An accurate chromatographic (silica gel) procedure for the quantitative measurement of the stable citric acid cycle acids and certain noncycle acids in urine was developed. The identity of the isolated acids was verified by paper chromatography. The method was applied to a study of urinary excretion of the cycle and other acids during certain alterations in acid-base balance in eight normal subjects, and one diabetic patient. During a “basic” regimen, the “alkaline tide,” and “respiratory alkalosis,” a significant increase in the excretion of citric acid occurred, with no significant change in that of the other cycle and noncycle acids. The “acidic” regimen produced a uniform decrease in the excretion of citrate to values approaching statistical significance; there was no consistent alteration in the excretion of the other acids. A similar decrease in the excretion of citric acid was observed in the patient during diabetic acidosis. It is concluded that of the Krebs cycle and other acids studied, the urinary excretion of only citric acid varies with alterations in acid-base balance. Submitted on February 10, 1961

INHERITANCE OF SUSCEPTIBILITY TO CONGENITAL DEFORMITY

PEDIATRICS ◽  
1959 ◽  
Vol 23 (1) ◽  
pp. 245-251
Author(s):  
Meredith N. Runner
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Carbohydrate Metabolism ◽  
Neural Tube ◽  
Ketone Body ◽  
Citric Acid Cycle ◽  
Congenital Deformity ◽  
Stomach Tube ◽  
Fasting Period ◽  
Acid Cycle

Fasting for 24 hours during the ninth day of pregnancy resulted in 22% of the fetuses having either cranioschisis or deformed ribs or both at 18 days post coitum. The fasting treatment affected neither the frequency of pregnancies following matings nor the incidence of prenatal mortality. Fetuses were protected from the fasting effect by relatively small quantities of a variety of nutrients, i.e., glucose, ketone-body or amino acids administered by stomach tube during the fasting period. The array of protective compounds suggested that they acted by supplying substrate for the citric acid cycle. Four teratogenic treatments (insulin, iodoacetate, x-methylfolic acid and fasting) produced similar abnormalities of development. A metabolic scheme is presented to suggest that each of these agents may interfere with reactions in the citric acid cycle. Administration of nutrients during the fasting period and use of teratogenic agents have provided circumstantial evidence that carbohydrate metabolism may be selectively critical for morphogenesis of embryonic neural tube and for differentiation of precartilaginous mesenchyme.

scholarly journals THE QUANTITATIVE HISTOCHEMISTRY OF THE SYMPATHOADRENAL SYSTEM II. ENZYMES OF THE CITRIC ACID, PENTOSE PHOSPHATE AND GLYCOGENOLYTIC PATHWAYS

1973 ◽  
Vol 21 (5) ◽  
pp. 483-487
Author(s):  
JAMES S. NELSON
Keyword(s):  
Citric Acid ◽  
Pentose Phosphate Pathway ◽  
Sympathetic Ganglion ◽  
Citric Acid Cycle ◽  
Sympathetic Neurons ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Pentose Phosphate ◽  
The Other ◽  
Acid Cycle ◽  
Neuronal Groups

The activities of enzymes from the citric acid cycle, pentose phosphate pathway and glycogen cycle were measured in collections of sympathoadrenal cells and compared with other neuronal groups. Enzymes from each pathway are found in groups of sympathetic neurons and adrenal medullary cells. The citric acid cycle has the highest capacity among glucose pathways in sympathoadrenal cells. Differences in glycolytic and citric acid cycle capacities between sympathetic ganglion and the other neuronal groups may be related to differences in capillary density. The capacity of the pentose phosphate pathway and reduced nicotinamide adenine dinucleotide phosphate-linked isocitric dehydrogenase is higher in sympathoadrenal cells than in the other cells surveyed. The enzyme activities in sympathetic ganglion are in excess of those needed to sustain the rates of glucose metabolism previously observed in this structure.

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