Cation Transport in Normal Human Red Cells Treated with Sulfhydryl Compounds

Journal/Book: Separatum EXPERIENTIA 22 32 (1966) Birkhäuser Verlag Basel (Schweiz). 1966;

Abstract: Istituto di Clinica Medica dell'Univeysità di Milano (Italy) June 21 1965. Some of us have recently observed1 that treatment of normal human red cells with AET (2-amino-ethylisothiouronium bromide) or cysteine under suitable experimental conditions modifies them in such a way that their behaviour in some in vitro hemolysis tests becomes similar to that of paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes. The effect is supposedly due to the -SH groups that both substances possess. So far a few enzymatic properties of these treated red cells have been investigated and related to those of PNH erythrocytes2. Since in vitro studies with K42 have recently shown3 that PNH red cells have normal K+ influx and efflux rates we have investigated whether the treatment with AET or cysteine modifies the cation transport of normal human erythrocytes. The blood of seven healthy adults was drawn with heparin; the red cells were separated by centrifugation and washed thrice with saline. An aliquot was treated with the above-mentioned sulfhydryl compounds as previously described1. (The Ham's test was performed an each sample to ascertain that the PNH-like behaviour had been achieved.) Another aliquot was similarly handled but no altering substance was added; it was used as control. All these red cell aliquots were successively resuspended in autologous plasma and stored at 4°C for 5 days as described elsewhere4. Each sample was then divided into 6 separate aliquots of 5 ml: 3 of these were immediately centrifuged and the remaining 3 were incubated at 37°C for 3 h in a Dubnoff shaker moving at a rate of 50 oscillations/min. K+ concentration was measured in the plasma of all the aliquots before and after incubation of the blood with a Beckman DU flame photometer. K+ uptake by the cells was calculated by differente according to the method of KAHN and ACHESON5 determining the hematocrit value before and after incubation. Results are summarized in the Table. It is seen that during the incubation both the control and treated red cells removed measurable quantities of K+ from the plasma against a concentration gradient : hence by an active mechanism. This phenomenon was demonstrable in spite of the concomitant increase of hemolysis produced - especially in treated cell samples - by warming and shaking which caused a passive shift of K+ from the lysed cells to the plasma. The analysis of variance showed that the differences of K+ uptake between the three groups (control and treated red cells) were not significant (P > 0.2). ... ___MH

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