Irreversible changes in rat erythrocyte Na+ transport systems with progesterone and estradiol administration

In order to test whether alterations in Na+ transport systems occurring in women when the hormonal status is disturbed such as in pregnancy, under contraceptive or estradiol therapy are a direct result of hormonal action on these transport systems, Na+,K+-pump Na+,K+ outward cotransport and passive Na+ permeability were measured in erythrocytes of ovariectomized rats receiving estradiol or progesterone. No significant changes in Na+,K+-pump were observed in either conditions. Conversely, progesterone was found to decrease Na+, K+-cotransport and estradiol to increase this system, whereas both steroids increased passive Na+ permeability.