Which of the following is a peptide hormone which stimulates production of RBCs?

Erythropoietin (EPO) is a peptide hormone that stimulates erythropoiesis, which is the process of red blood cell production. It is primarily produced and released by the kidneys, although a small amount can also be produced in the liver. EPO is released in response to low oxygen levels in the body, typically detected by special cells in the kidneys called peritubular cells.

When the oxygen levels in the blood are low (a condition known as hypoxia), such as at high altitudes or in cases of anemia or lung diseases, the kidneys release erythropoietin. Erythropoietin then travels through the bloodstream to the bone marrow, where it stimulates the production of red blood cells from precursor cells called erythroblasts. These red blood cells carry oxygen from the lungs to the body's tissues, helping to maintain proper oxygen levels and support various physiological functions.