Fig. 2. Effect of E2 on ER-α and ER-β present in membrane of RBCs from pre-menopausal and post-menopausal females as well as from males. To evaluate whether ERs are constitutively present in the RBC membrane, or if they are recruited to the membrane after activation of the E₂- ligand, experiment were carried out by western blot in RBCs membranes, treated for 5 min with 10 and 30nM of E₂. Representative blotting of ER-α (B) and ER-β (D) membrane levels, and densitometry analysis of eight different experiments are shown. (A and C, respectively). After treatment with E₂, the presence of ER-α in membrane significantly increases in RBCs from pre-menopausal and post-menopausal females and from males (A). Similar trend is also observed for ER-β membrane content (C). * p<0.05; ** p<0.001.