HUMAN ERYTHROCYTE SHAPE REGULATION - INTERACTION OF METABOLIC AND REDOX STATUS

The echinocyte-to-discocyte shape recovery of metabolically depleted e rythrocytes is compromised by sulfhydryl reducing agents (Truong, H.-T .N., Ferrell, J.E., Jr. and Huestis, W.H. (1986) Blood 67, 214-221). I n the presence of dithiothreitol (DTT) and sugars, crenated cells reco ver normal discoid shape transiently, but then develop the invaginatio ns and intracellular inclusions of stomatocytes. The stomatogenic effe cts of DTT were investigated in erythrocytes recovering from crenation induced by several independent mechanisms. Cells crenated by direct m anipulation of the membrane bilayer (lysophosphatidylcholine incorpora tion) recovered discoid shape similarly in the presence and absence of the reducing agent. In contrast, resealed ghosts and cells crenated b y Mg2+ depletion or Ca2+ loading did not maintain stable discoid morph ology in the presence of DTT, proceeding further to form stomatocytes. Thus cell crenation by expedients that involve cellular metabolic pro cesses develop a redox-related morphological instability that is not f ound in amphipath-crenated cells.