Erythropoietin is a glycoprotein secreted mainly by the kidney in response to cellular hypoxia; it stimulates red blood cell production (erythropoiesis) in the bone marrow. The juxtaglomerular cells of kidney produce a peptide hormone called erythropoietin which stimulates erythropoiesis (formation of RBC).
Juxtaglomerular cells produce renin, which converts angiotensinogen to angiotensin.