AJP - Cell Physiology, Vol 261, Issue 3 C423-C427, Copyright © 1991 by American Physiological Society
Estrogen modulates phospholipid acylation in red blood cells: relationship to cell aging
J. Le Petit-Thevenin, B. Lerique, O. Nobili and J. Boyer
Institut National de la Sante et de la Recherche Medicale Unite 260, Faculte de Medecine Timone, Marseille, France.
Ethinyl estradiol administered in vivo to female rats resulted in a mild
anemia with a 120% increase in reticulocytosis. Consistent with a previous
study, the red blood cell cholesterol-to-phospholipid molar ratio was
decreased by 25%, whereas fatty acyl incorporation was significantly
increased into phosphatidylethanolamine (PE) and not into
phosphatidylcholine (PC), the major acyl acceptor in red blood cells.
Analysis of this estrogen-dependent acylation increase as a function of
cell age indicated that it was not expressed in reticulocytes but in
erythrocytes and was associated with cell aging. Estrogen was further shown
to increase the red blood cell susceptibility to peroxidation generated by
incubation with H2O2. Altogether, the results suggest that estrogen
indirectly increases phospholipid acylation in red blood cells by
decreasing protection against oxidative damage, thereby favoring the action
of endogenous phospholipases against oxidized substrates. This occurs
predominantly in PE of oldest cells because 1) PE, being more unsaturated
than PC, is more sensitive to oxidation, and 2) susceptibility to oxidation
increases with cell age.
