Dear Prof. Wefak Jbori Albazi

Yes, I know, the hormone estrogen affects RBCs in both males and females, though the effects are more noticeable in females due to higher circulating levels.

Although estrogen is often considered a "female" hormone, it is present and has important functions in males. In males, the effects of estrogen on RBCs are less pronounced but still relevant. While testosterone stimulates erythropoiesis, estrogen works to counteract this effect, acting as part of the overall regulatory mechanism governing red cell production.

Estrogen, particularly estradiol, has been shown to suppress the production of new RBCs in the bone marrow, leading to lower total counts and hemoglobin levels in females compared to males. This inhibitory effect is likely mediated through the estrogen beta receptor (ERβ), which influences transcription factors vital for erythroid cell maturation.

Studies have confirmed that hematopoietic stem cells have estrogen receptors, allowing the hormone to influence the self-renewal and proliferation of these cells. Research indicates that estrogen can influence the deformability of RBCs, which is their ability to change shape and squeeze through tiny capillaries. Higher estradiol concentrations are associated with increased RBC deformability.

Regards,

Malcolm Nobre

Dear Malcolm Nobre

Thank you for your response. Indeed, estrogen has specific receptors, ERα and ERβ, expressed in most body cells, including red blood cells and their progenitors. Through these receptors, especially ERβ, estrogen regulates erythropoiesis and RBC function, which also explains the hematological changes observed in women during menopause.