erythropoietin
Concise Oxford English Dictionary © 2008 Oxford University Press:
erythropoietin /ɪˌrɪθrə(ʊ)pɔɪˈɛtɪn/
▶noun Biochemistry a cytokine (type of protein) secreted in the kidneys that increases the rate of production of red blood cells in response to falling levels of oxygen in the tissues.
'erythropoietin' also found in these Oxford entries:

