This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Renal physiology, Subject name: Physiology
Erythropoietin is inhibited by 
Select and explain. 
A. Estrogen, B. Progesterone, C. Thyroxine, D. Testosterone
A: Estrogen
Answer: A: Estrogen 
Explanation: Glycoprotein hormone that controls erythropoiesis, or red blood cell production. Estrogen inhibits the erythropoietin whereas testosterone stimuates production . Ref: Ganong's Review of Medical Physiology; 24th edition; page no: 709