Cell volume regulation in hemoglobin CC and AA erythrocytes.
Swelling hemoglobin CC erythrocytes stimulates a ouabain-insensitive K flux that restores original cell volume. This volume regulatory pathway was characterized for its anion dependence, sensitivity to loop diuretics, and requirement for Na. The swelling-induced K flux was eliminated if intracellular chloride was replaced by nitrate and both swelling-activated K influx and efflux were partially inhibited by 1 mM furosemide or bumetanide. K influx in swollen hemoglobin CC cells was not diminished when Na in the incubation medium was replaced with choline, indicating Na independence of the swelling-induced flux. Identical experiments with hemoglobin AA cells also demonstrated a swelling-induced increase in K flux, but the magnitude and duration of this increase were considerably less than that seen with hemoglobin CC cells. The increased K flux in hemoglobin AA cells was likewise sensitive to anion replacement and to loop diuretics and did not require the presence of Na. These data indicate that a volume-activated K pathway with similar transport characteristics exists in both hemoglobin CC and AA red cells.
D001692:Biological Transport; D002034:Bumetanide / Q000494:pharmacology; D002712:Chlorides / Q000097:blood; D004912:Erythrocytes / Q000166:cytology / Q000502:physiology*; D004913:Erythrocytes, Abnormal / Q000166:cytology / Q000502:physiology*; D005665:Furosemide / Q000494:pharmacology; D006445:Hemoglobin C Disease / Q000097:blood*; D006801:Humans; D011188:Potassium / Q000097:blood; D014882:Water-Electrolyte Balance
D002712:Chlorides; D002034:Bumetanide; D005665:Furosemide; D011188:Potassium