The Internal Distribution of Hydrogen Ions With Varying Degrees of Metabolic Acidosis1

When a mineral acid is administered to animal or man, a substantial fraction is buffered in sites other than blood or interstitial fluid. Van Slyke and Cullen (1) first observed that total blood vol- ume could account for the buffering of only onesixth of a mineral acid load and suggested that buffer substances throughout the body, including those of the tissues, are utilized in the defense against metabolic acidosis. Recent studies in sev- eral laboratories have provided more detailed quantitative data on the internal distribution of administered hydrogen ions. Swan and Pitts (2) in nephrectomized dogs and Schwartz, Jenson, and Relman (3) in normal human subjects have dem- onstrated that only about one-half of a mineral acid load is buffered in the extracellular space and red blood cells. The remaining hydrogen ions exchange with sodium and potassium from tissue and bone and are presumably buffered in these areas.