1. In the presence of 1.2mm-atractyloside oxygen uptake by rat diaphragm muscle incubated with 5.6mm-glucose decreases, as well as glycogen synthesis and carbon dioxide production. Lactate formation from glucose increases, but that of phosphoglycerate diminishes fivefold. 2. When pyruvate is used as substrate, atractyloside decreases oxygen uptake. 3. The specific radioactivity of the (14)CO(2) (mumoles of (14)CO(2)/mumole of oxygen), calculated at concentrations of [1-(14)C]pyruvate between 0.091mm and 91mm, lies between 3.1x10(-4) and 5.7x10(-1). Atractyloside increases the specific radioactivity of the (14)CO(2) with the lowest concentrations of substrate and has no effect when the substrate concentration is 91mm. 4. No appreciable effect of atractyloside on the anaerobic production of (14)CO(2) from [1-(14)C]pyruvate at various incubation times and various concentrations is found. 5. It is suggested that atractyloside induces anaerobic conditions in the tissue. Further, it produces a rise in the pyruvate concentration and an ATP deficiency in the cell. Consequently it stimulates pyruvate dismutation, and glycolysis, to which phosphorylation is linked at the substrate level.

Adenosine Triphosphate↗

PubMed1968

Effect of triperidol on carbohydrate and amino acid metabolism in rat brain-cortex slices.

1. The effect of triperidol on the metabolism of glucose, pyruvate, glutamate, aspartate and glycine was studied with rat brain-cortex slices, U-(14)C-labelled substrates and a quantitative radiochromatographic technique. 2. Triperidol at a concentration of 0.2mm decreased the oxygen uptake and the (14)CO(2) production by about 30% when glucose, pyruvate and glutamate were used as substrates, whereas no effects were observed with aspartate and glycine. 3. The drug did not alter qualitatively the metabolic pattern of the substrates. 4. Quantitatively, triperidol decreased the incorporation of (14)C from [U-(14)C]glucose and [U(14)-C]-pyruvate into glutamate, glutamine and gamma-aminobutyrate but not into lactate, alanine and aspartate. The overall utilization rates of glucose and pyruvate were decreased. The relative specific radioactivities of glutamate and aspartate were also decreased. 5. Triperidol increased the rate of disappearance of U-(14)C-labelled glutamate, aspartate and glycine from the incubation medium, and altered the distribution of their metabolites between medium and tissue. 6. No appreciable effect of triperidol on [1-(14)C]galactose disappearance was found.

Amino Acids↗

PubMed1968