“…As the result, dual-effect was observed in the sense that the hormone was acceleratory in comparatively low concentrations and inhibitory in higher concentrations. More recently, Suzuki (1954);working on the effect of relatively high concentrations of thyroxine upon succinic dehydrogenase, and cytochrome oxidase as observed manometrically, and succinic cytochrome c reductase as measured photometrically in mouse liver homogenate, showed that succinic dehydrogenase together with cytochrome oxidase were activated, while succinic cytochrome c reductase suffered from inhibitory effect of the hormone.…”