title: Molecular biology of polycythemias.
abstract: Polycythemia is literally translated as "many cells in the blood". Only erythrocytosis (an alternative term for these disorders) produces polycythemia since leukocytes and platelets are present in blood in far smaller proportions. Polycythemia may be due to increased proliferation or decreased apoptosis of erythroid progenitors, or to delayed erythroid differentiation with an increased number of progenitor cell divisions. Prolonged red cell survival, another theoretical cause of polycythemia, has not yet been described and with intact regulatory mechanisms is unlikely to occur. Primary polycythemias result from abnormalities expressed in hematopoietic progenitors. In contrast, circulating factors cause secondary polycythemia (1). There are acquired and congenital causes of both primary and secondary polycythemia (1).
authors.affiliation: Division of Hematology/Oncology, Baylor College of Medicine, Houston, Texas 77030, USA.
authors.forename: J T
authors.initials: JT
authors.lastname: Prchal
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D004920:Erythropoiesis; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D011086:Polycythemia / Q000378:metabolism / Q000503:physiopathology*; D011087:Polycythemia Vera / Q000503:physiopathology; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin / Q000378:metabolism; D017467:Receptors, Erythropoietin / Q000378:metabolism
chemical_list: D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin; D017467:Receptors, Erythropoietin; D000804:Angiotensin II; D007334:Insulin-Like Growth Factor I