EPO production by muscle…….

“Erythropoietin is responsible for regulating the growth and development of red blood cells. Reports conflict on whether skeletal muscle is able to produce erythropoietin and release it into circulation and if exercise affects this.”

“To understand if skeletal muscle cells were able to stimulate erythropoiesis, independent of other cell types found in skeletal muscle, we used myoblast-conditioned media to treat bone marrow and to measure erythropoiesis through flow cytometry. We also measured erythropoietin expression and hypoxia in mice subjected to an exercise protocol designed to induce skeletal muscle oxygen stress.”
“Hypoxia increased erythropoietin expression in C2C12 myoblasts, myotubes, and primary myoblasts in vitro by 50% to 130%.”
“Compared with unexercised controls, exhaustive exercise increased skeletal muscle HIF1α levels by 50% and HIF2α levels by 20%. Moreover, exercised skeletal muscle erythropoietin expression was 70% higher.”

“These results demonstrate that skeletal muscle produces erythropoietin in a hypoxia and HIF-dependent manner and that hypoxia-treated muscle is capable of stimulating erythropoiesis in vitro.”

J.M. Baker, et al
Skeletal Muscle Erythropoietin Expression Is Responsive to Hypoxia and Exercise
Medicine & Science in Sports & Exercise: — Volume 48 #7 — July 2016 — page 1294