The metabolism of normal and tumour tissue

Abstract

THE methods previously described in this series make possible the accurate measurement of the true respiratory quotient and respiration of tissues suspended in a phosphate medium Additional points of technique were described recently [Dickens and 8imer, 1933]. These methods may be applied to all types of tissue; but when the bicarbonate method is applied to tissues in which the aerobic acid production is high compared with the respiration, the glycolysis may not persist throughout the experiment at its initial level. For with such tissues, although it is adequate with others, the amount of bicarbonate solution which can be used may be unable to prevent an undue fall of PHI and increase of lactate concentration in the medium. With the simple manometer used, and also with the Barcroft manometer as applied to the measurement of respiratory quotient by Dixon and Keilin [1933], the permissible bicarbonate reserve is limited by the length of the manometer limb and the density of the manometer fluid. Increase of the former is inconvenient; increase in the latter results in loss of sensitivity. The difficulty has been overcome by the application of the constant-volume differential manometer [Dickens and Greville, 1933] to the respiratory measurements. It is now possible to use a sensitive manometer fluid (Brodie fluid of sp. gr. approximately 1), and to have a volume of bicarbonate solution such that, even with highly glycolysing tissues, the glycolysis remains nearly constant throughout. The conditions are strictly comparable with those of the Warburg [1924] two-vessel method; but whereas Warburg's method gives only the 02 consumed and the total C02 produced by respiration and glycolysis, the method now described gives the true respiratory quotient and the true aerobic glycolysis, respiratory C02 and O2-uptake.