An increase in the concentration of 2 – 3 Biphosphoglycerate (2,3 DPG) may be seen in all of the following except
**Core Concept**
The question is based on the regulation of oxygen binding to hemoglobin, specifically the role of **2,3-Bisphosphoglycerate (2,3-DPG)**, a byproduct of glycolysis in red blood cells. 2,3-DPG binds to deoxyhemoglobin, reducing the affinity of hemoglobin for oxygen, thereby facilitating the release of oxygen to tissues.
**Why the Correct Answer is Right**
An increase in 2,3-DPG concentration is a physiological response to conditions where there's a need for increased oxygen delivery to tissues, such as at high altitudes or in anemic states. This mechanism helps in adapting to lower oxygen levels by ensuring that the oxygen bound to hemoglobin is more easily released.
**Why Each Wrong Option is Incorrect**
**Option A:** Typically, an increase in 2,3-DPG is seen in conditions like anemia, where the body tries to compensate for the reduced oxygen-carrying capacity of the blood.
**Option B:** High altitude exposure leads to an increase in 2,3-DPG as an adaptive mechanism to enhance oxygen delivery to tissues in low oxygen environments.
**Option C:** Chronic lung disease can lead to hypoxia, prompting an increase in 2,3-DPG to facilitate oxygen release.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that 2,3-DPG levels increase in response to hypoxia, helping to improve oxygen delivery to tissues by reducing hemoglobin's affinity for oxygen. This is crucial for understanding adaptations to high-altitude environments or chronic hypoxic conditions.
**Correct Answer:** D.