Is Oxygen Consumption of Surviving Tissues Determined by the Oxygen Tension of the Suspension Medium?

Oxygen tension in the suspension medium and oxygen uptake of the isolated diaphragm of the mouse have been determined simultaneously with systematic variation of shaking frequency and oxygen concentration of the gas phase. Oxygen tension in the suspension medium reaches its final value during the usual equilibration period of 10 minutes and remains constant for the whole measuring period. Each combination of shaking frequency and oxygen concentration of the gas phase results in a reproducible value of oxygen tension in the medium. Equal oxygen tension in the fluid phase can be attained by different combinations of shaking frequency and oxygen concentration of the gas phase. Oxygen uptake at the same oxygen tension of the suspension medium can be very different; it is the higher the higher the shaking rate in the combination. On the other hand the same oxygen consumption of the tissue samples can be observed with highly different oxygen tensions in the medium. It must be concluded from the data in this paper, that the influence of shaking rate per se on the oxygen uptake of isolated tissue can be of the same order as the influence of oxygen tension.