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 in kidney is secreted by 
Select and explain. 
A. Juxtaglomerular cells, B. PCT cells, C. Interstitial cells in peritubular capillaries, D. Capillaries of glomerulus
C: Interstitial cells in peritubular capillaries
Answer: C: Interstitial cells in peritubular capillaries 
Explanation: Interstitial cells in paritubular capillaries releoses erythroportin in responce to hypoxia.