oxygen sensors

Q: What is the body's major stimulus for Erythropoietin (EPO) production?

Answer: decreased oxygen delivery 

Though simple, an essential concept is to understand that the human body is designed to respond against reduced oxygen delivery, either caused by anemia or hypoxemia. The human body contains factors called hypoxia-inducible factor (HIF), comprised of alpha and beta subunits (HIF-1-alpha and HIF-1-beta). HIF regulates EPO transcription and is popularly known as "oxygen sensors." 

It can be said that the 'oxygen sensor' regulates life. Low oxygen delivery stimulates the O2 sensor. These sensors are designed to perform many other associated mechanisms to regain and maintain normoxia. In normal humans, oxygen quickly destroys these sensors (negative feedback) to protect against polycythemia.

#hematology

References:

1. Semenza GL. Oxygen sensing, homeostasis, and disease. N Engl J Med 2011; 365:537.

2. Franke K, Gassmann M, Wielockx B. Erythrocytosis: the HIF pathway in control. Blood 2013; 122:1122.

3. Semenza GL. Involvement of oxygen-sensing pathways in physiologic and pathologic erythropoiesis. Blood 2009; 114:2015.

4. Yoon D, Ponka P, Prchal JT. Hypoxia. 5. Hypoxia and hematopoiesis. Am J Physiol Cell Physiol 2011; 300:C1215.