Erythropoietin is secreted mainly by: March 2013

Ans. A i.e. KidneyErythropoietin/HematopoietinIt is produced by interstitial fibroblasts in the kidney in close association with peritubular capillary and tubular epithelial cells.It is also produced in perisinusoidal cells in the liver.While liver production predominates in the fetal and perinatal period, renal production is predominant during adulthood.It is a glycoprotein hormone that controls erythropoiesis, or red blood cell production.It is a cytokine (protein signaling molecule) for erythrocyte (red blood cell) precursors in the bone marrow.