GLOSSARY

Erythropoietin, or EPO, is a glycoprotein hormone, about 90 percent of which is made in the kidneys (by peritubular fibroblast-like cells in the renal cortex) and the rest in the liver. EPO’s main job is to stimulate the bone marrow to produce red blood cells.

Control of Secretion

The main stimulus for EPO release is low tissue oxygen (hypoxia). In hypoxia, the protein HIF (hypoxia-inducible factor) becomes stable and switches on the EPO gene. Anaemia, high altitude and lung disease increase EPO release.

Effects

EPO binds to its receptor on red cell precursors in the bone marrow, prevents their programmed death and speeds their proliferation and maturation. A rise in reticulocytes is seen within 3–4 days and a rise in haemoglobin within 2–6 weeks.

Clinical Use

Recombinant EPO is used to treat anaemia caused by chronic kidney disease and chemotherapy. HIF-PH inhibitors