This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Erythropoietin production is inhibited by ? 
Select and explain. 
A. Estrogen, B. Progesterone, C. Thyroxine, D. Testosterone
A: Estrogen
Answer: A: Estrogen 
Explanation: Ans. is 'a' i.e., EstrogenThe most impoant stimulus for erythropoietin secretion is hypoxia.Other stimulus that can increase its secretion are cobalt salts, androgens, alkalosis due to high altitude, and catecholamines beta-adrenergic mechanism.