Granulocyte colony-stimulating factor (G-CSF), also known as CSF3, is a protective cytokine with anti-inflammatory effects. G-CSF is important in promoting survival of the granulocytic lineage cells and proliferation and migration of neutrophils and trophoblast cells. G-CSF exerts its effects by binding to its receptor G-CSFR, in turn activating the JAK/STAT and Ras/Raf/MAP kinase pathways (PMID 9015216, 7509213, 9933603). G-CSF potently stimulates the proliferation and release of peripheral blood progenitor cells into the bloodstream and is therefore used to treat neutropenia after chemotherapy (PMID 7524753, 3264199). Furthermore, G-CSF levels are elevated upon intensive exercise leading to increased neutrophil counts, which are predominantly due to delayed neutrophil apoptosis (PMID 18524991).