Estrogen Levels Regulate Platelet Synthesis

Researchers have found that estrogen in the form of estradiol plays a key regulatory role in the process by which bone marrow megakaryocytes produce blood platelets.

Megakaryocytes are giant cells in the bone marrow that shed their cytoplasm in small fragments, which become the blood platelets. Previous studies had shown that expression by megakaryocytes of the p45 NF-E2 transcription factor was required for platelet production. In the current study, investigators at Riken, The Institute of Physical and Chemical Research (Japan), used a mouse model to identify the mode of action of p45 NF-E2.

They reported in the December 1, 2003, issue of Genes & Development that p45 NF-E3 activated the 3b-HSD gene, and that this gene encoded an enzyme that regulates synthesis of estradiol. The importance of estradiol to platelet formation was demonstrated by adding extra estradiol to a megakaryocyte culture. Platelet formation was increased by more than 50% in the presence of added estradiol, while the inhibition of estradiol receptors blocked platelet formation in live mice.

Recognition of the role of estradiol in platelet synthesis will allow researchers and clinicians to approach problems of too many or too few platelets through the manipulation of estrogen levels.



Related Links:
Riken