What is the relationship between Testosterone and Erythropoiesis

Question

Dr. I have been told that men typically have more RBCs than Women primarialy due to the presence of testosterone. Can you tell me about the relationship between Testosteronr and Erythropoiesis, what are the mechanisms that testosterone effects that in turn effect RBC production. Thanks much, I would greatly appreciate a deeper understanding here. Regards; Richard

Answer

Hello Richard,

That's a short simple question that unfortunately has a very long and quite complicated answer that is beyond the scope of this forum. However, I'll try to hit the high points for you. Women have lower "normal" ranges of RBC's and hemoglobin than men, for several reasons. Menstruation, for instance, is a source of monthly blood loss. Hormones, including testosterone, also are an important part of the picture.

Erythropoiesis is the production of new red blood cells. This is accomplished primarily in the bone marrow, the red blood cell factory, so to speak. Erythropoiesis is stimulated primarily by erythropoietin (hence, the clever naming of that hormone!). Erythropoietin is produced in the kidneys. Androgens, including testosterone, are another type of hormone. One of the effects of androgens is to increase the production of erythropoietin. Another is to increase the responsiveness of immature bone marrow cells to the effects of erythropoietin. Simplistically, testosterone increases the output and effectiveness of erythropoietin, which in turn stimulates the production and regulation or red blood cells. Testosterone, and other androgens, has many other effects as well, which is why it is not used primarily for erythropoiesis.

Does that make any sense whatsoever? Sorry for the complex response, but hey, you asked the question! Hope that helps.

Dr. Bob