Abstract
Artificial media, approximating the normal fluid environment of cells, are widely used for the study of the metabolism of excised tissues. In the differential method of Warburg 1 it is possible to employ a solution which has the physiologically normal calcium ion concentration of 1 millimol per liter at pH 7.4. The composition of the solution which we refer to as our “standard” solution of reference is given in Table I.
Serum has been used successfully by Warburg 2 as a medium for the study of the metabolism of excised tissue. The complication in technique which arises from the buffer action of the serum proteins has been one of the drawbacks to its widespread use in the differential method, however. On the other hand, cerebrospinal fluid has all the biological advantages of serum and, in addition is protein-free. This permits its direct use as a fluid medium for excised tissues. Through the cooperation of the Department of Neurology, we have had an opportunity to compare the metabolism of tissues in cerebrospinal fluid with that in our standard salt solution medium. The results are given in Table I. In every instance the oxygen consumption has been higher, and the aerobic glycolysis has, when present, been lower, in the cerebrospinal fluid than in the standard salt solution.
The reason why the cerebrospinal fluid should thus appear to be a superior medium for the metabolism of mouse liver is not known, although we are not inclined to attribute its superiority to differences in concentrations of inorganic ions.
An example of one way in which the metabolism of tissues may be markedly increased by the presence of organic substances—in this instance a reversibly oxidizable dye, indigo disulfonate—is also shown in the table.
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