P. Emmelot

The metabolism of neoplastic tissues: carbon dioxide production from specifically 14C-labelled glucose by normal and neoplastic tissues.

The Metabolism of Neoplastic Tissues: Carbon Dioxide Production from Specifically 14 C-Labelled Glucose by Normal and Neoplastic Tissues

Deoxycytidylate Deaminase and Thymine Catabolic Activity of Transplanted Mouse and Rat Hepatomas and their Histology.

ImagesFigs. 5-8Figs. 1-4Figs. 9-12

The Metabolism of Neoplastic Tissues: the Inter-relationship between Oxidative and Glycolytic Mechanisms in Ascites Tumour Cells

The Metabolism of Neoplastic Tissues: the Inter-relationship between Oxidative and Glycolytic Mechanisms in Ascites Tumour Cells

Swelling of normal, preneoplastic and neoplastic liver mitochondria

The swelling of rat and mouse liver mitochondria, isolated in 0.30 M sucrose and incubated in sucrose-Tris of pH 7.4 at 22±1°C, in response to succinate, adenine nucleotides (10−5 M), malonate, thyroxine, and DNP, separately or in various combinations, was measured. It was found that both the spontaneous and thyroxine-induced swelling of fresh mitochondria were counteracted by succinate and, to a still greater extent, by succinate plus adenine nucleotide (ADP≥ATP≫ or > AMP). The protection was abolished by malonate or DNP. The protection against swelling afforded by succinate to fresh mitochondria was followed by a phase of rapid swelling. Progressive ageing or frequent washing of the particles, prior to their incubation, led to a reduction or abolition of the protective effect. It was concluded that mitochondrial swelling was governed by the degree of intrinsic stability of the isolated particles. Die Schwellung von in 0,30 M Saccharose isolierten und in Saccharose-Tris von pH 7,4 bei 22±1°C inkubierten Mitochondrien aus Mäuse- und Rattenlebern wurde gemessen nach Zusatz von Succinat, Adeninnucleotiden (10−5 M), Malonat, Thyroxin und DNP, allein und in verschiedenen Kombinationen. Sowohl die spontane wie die thyroxininduzierte Schwellung frischer Mitochondrien wird durch Succinat und noch mehr durch Succinat und Adeninnucleotide (ADP≥ATP≫ oder > AMP) gehemmt. Die Hemmung wird aufgehoben durch Malonat oder DPN. Auf die Hemmung der Schwellung von frischen Mitochondrien durch Succinat folgt eine Phase schneller Schwellung. Allmähliche Alterung oder wiederholte Waschungen von den Mitochondrien vor der Inkubation führen zu einer Verringerung oder Aufhebung des hemmenden Effektes des Succinats. Daraus wird gefolgert, daß die mitochondriale Schwellung von dem Grade der Eigenstabilität der isolierten Partikel abhängig ist.

The metabolism of neoplastic tissues

The incorporation of tracer from acetate-1-C14 into the respiratory carbon dioxide, protein-bound amino acids, cholesterol and long-chain fatty acids of surviving tumor slices has been studied in the presence of malonate, monoiodoacetate, 2,4-dinitrophenol and methylene blue. The effect of anaerobiosis on cholesterol and fatty acid synthesis was also investigated. It is shown that for fatty acid and cholesterol synthesis in the tumor slices to continue unhampered different requirements have to be satisfied. Cholesterogenesis was dependent upon the normal functioning of the citric acid cycle, whereas lipogenesis could cover at least part of its requirements with glycolytic reactions. Experiments with 2,4-dinitrophenol suggested that the activation of acetate, which is required before the substrate can enter metabolic reactions, is dependent upon the adenosine triphosphate supplied by the citric acid cycle. The effect of the inhibitors on the hexose monophosphate oxidative pathway was also studied.

The Metabolism of Neoplastic Tissues: Demonstration of Intermediates and Reaction Sequences of the Hexose Monophosphate Oxidative Pathway

The Metabolism of Neoplastic Tissues: Demonstration of Intermediates and Reaction Sequences of the Hexose Monophosphate Oxidative Pathway

The metabolism of neoplastic tissues: further observations on the relative rates of acetate and pyruvate utilization by surviving tissue slices of mouse tumors.

The relative rates of the incorporation of tracer from equimolar amounts of pyruvate-2-C14 and acetate-1-C14 into respiratory carbon dioxide, protein-bound amino acids, cholesterol and long-chain fatty acids were studied using surviving tissue slices of mouse tumors. The strains studied consisted of two spontaneous and two transplanted mammary carcinomas, two transplanted sarcomas, one lymphosarcoma and two interstitial cell carcinomas of the testis. On account of the ratios of incorporation of C14 from the two precursors into the four compounds, it was concluded that enough of the metabolic characteristics of the various tumors of each group was retained to warrant a classification on this basis.

The metabolism of neoplastic tissues: the metabolic activity of normal and cancerous rat livers studied with acetate-1-14C in vitro.

In vitro studies with surviving tissue slices show that neither the activation nor the utilization of acetate-1-14C in four important metabolic sequences is impaired in the neoplastic rat liver following the feeding of p-dimethylaminoazobenzene. Incorporation of 14C from acetate-1-14C into the proteins is very markedly enhanced in the hepatoma and hepatoma-bearing liver as compared with that in the normal and precancerous liver. It is concluded that the citric acid cycle is markedly active in the neoplastic rat liver.