The author studied the effects of high hydrostatic pressure on respiration of liver tissue of frog (Rana nigromaculata). The results were obtained as follows. 1) After exposure to 300 kg/㎠ the oxygen consumption of liver tissue were accelerated and inhibited by 400-1500 kg/㎠ in proportion to the strength of applied pressure. 2) The oxygen consumption of liver tissue in the presence of citrate, acetate and glycerophosphate was accelerated at various hydrostatic pressures. 3) The oxygen consumption of liver tissue in the presence of succinate, glucose and pyruvate was inhibited at various hydrostatic pressure. 4) At relatively low pressure (300 kg/㎠), succinic dehydrogenase activity increased, but at moderate high pressure (500-800 kg/㎠) and ...