Physiology General 07823d63 Erythropoietin secretion occurs when: A Tissue pO2 concentration B T Tissue pH C T Tissue pCO2 concentration D T Hemoglobin High-Yield Explanation A i.e. 4, Tissue PO2 concentrationThe only physiological stimulus for erythropoietin secretion is Hypoxia or decreased paial pressure of oxygenQ.