Control of erythropoiesis and starting points for blood doping. The hormone Epo, which derives from kidneys and liver, stimulates the survival, proliferation, and differentiation of the erythrocytic progenitors in hemopoietic tissues. The enhanced release of reticulocytes leads to an increase in the blood hemoglobin concentration and, thus, the O2 capacity of the blood and the total Hb mass. Epo gene expression in the kidneys and the liver is controlled at the transcriptional level. Because the Epo enhancer is activated by the HIF, chemicals stabilizing HIF, such as cobalt and α-ketoglutarate competitors, increase Epo expression. GATA inactivators release the Epo promoter from the inhibition by GATA-2. Androgenic steroids and GH, respectively IGF-1, augment the production of Epo and the proliferation of erythrocytic progenitors.
