Effect of irradiation on oxygen consumption in relation to temperature.

Continuing the investigation of the peaks in oxygen consumption which have been shown to characterise the influence of temperature on animal tissues and which are dependent on the action of fatty acids, it was found that methyl-cholanthrene causes downward displacements of the peaks. Consequent on this observation a systematic investigation of the effects of irradiation of the tail of the rat was carried out, using the Vierordt method as a criterion of the intensity of oxidation. Moderate doses of γ/irradiation under normal conditions, in which the temperature of the tail of the rat is close to room temperature, result in pronounced upward displacements and, finally, disappearance of the peaks. Evidence is advanced to show that this is a result of changes in the fatty acids. As the physical state of the insoluble fatty acids alters within the biological range of temperature, further experiments were carried out in which the tail of the rat was maintained at higher temperatures during irradiation. When this temperature was above the normal central temperature all peaks were displaced downwards. When the temperature was held at a point between this and room temperature peaks ordinarily above the temperature of irradiation were displaced upwards and those below downwards. A peak in the immediate neighbourhood of the irradiation temperature expands into an extensive plateau. The results obtained with the Vierordt method were supported byin vitro determinations of the oxygen consumption.