Rate of Penetration of Ions into Erythrocytes

Abstract

Summary. The red corpuscles contain much larger amounts of acid soluble phosphorus compounds than the plasma. The difference is only maintained as long as an active process, an alternative phosphorylation and dephosphorylation, takes place in the corpuscles, a process which, was studied by measuring the rate of penetration of labelled phosphorus into the erythrocytes and the rate of incorporation of 32 P into the acid soluble P compounds present in the corpuscles. While labelled phosphate penetrates at about the same rate into the corpuscles of the human and the rabbit, it enters at a much slower rate the nucleated corpuscles of the hen and the frog. The amount of labelled phosphate which penetrates into the corpuscles of the rabbit at 0° was found to make out about 1/14 of the amount found at 37°. Incorporation of labelled phosphate into acid soluble P compounds, thus alternative dephosphorylation and phosphorylation, was found to go on in the blood hemolysate as well, though at a slower rate than in the intact corpuscles. A lowering of the temperature from 37° to 0° reduces the amount of labelled P incorporated into organic P compounds of the hemolysate to 1/4. The addition of KCN to blood reduces the formation of organic P compounds in the corpuscle markedly. The rate of penetration of phosphate into the corpuscles was also measured by accumulation experiments in which a part of the plasma chloride Was replaced by phosphate and the amount of phosphate which left the plasma determined at different intervals. The difference between the interchange of labelled and non‐labelled ions, present in the plasma and the corpuscles respectively, and the accumulation of ions in the corpuscles after raising the ionic concentration of the plasma is discussed and it is shown that only interchange experiments supply a direct measure of the hindrance of a phase boundary to the passage of ions. By using 32 P and 38 Cl, respectively, as indicators the percentage of plasma phosphate which penetrates per unit time into the corpuscles of the rabbit was found to be at least 100 times smaller than the percentage of plasma chloride penetrating into the corpuscles. The rate of penetration of sodium, using 24 Na as a tracer, Was found to be slower than the rate of intrusion of phosphate.