Fluctuation of Extracellular Fluid pH and the Effect of Rice Vinegar

Abstract

Extracellular fluid pH in the anterior tibial muscle of rats was estimated using a pH monitor with a temperature corrector. When the thigh artery was compressed with a finger to stop the blood flow around the anterior tibial muscle, the pH of the extracellular fluid showed a rapid reduction and recovered immediately after release of pressure. Inhalation of carbon dioxide also reduced the extracellular fluid pH. These results suggest that reduction of the extracellular fluid pH due to disturbance of blood circulation may be due to accumulation of carbon dioxide produced by the muscle. In addition, it was found that the extracellular fluid pH of diabetic rats was significantly reduced as compared to that of control rats. Oral administration of rice vinegar (kurozu) increased the extracellular fluid pH of diabetic rats slightly but significantly. The physiological significance of this reduction of extracellular fluid pH is discussed in relation to inhibition of insulin action.