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4 out of 16

Rise in 2-3 bisphosphoglycerate is seen in all except? (AIPG 2009)

A Chronic anemia
B Chronic hypoxia

C Inosine
D Hypoxanthine

Ans. D Hypoxanthine

Factors affecting the concentration of 2,3-BPG in the red cells include pH. Because acidosis inhibits red cell glycolysis, the 2,3-BPG concentration falls when the pH is low.

I. Thyroid hormones, growth hormone, and androgens increase the concentration of 2,3-BPG and the P50.


a. Exercise has been reported to produce an increase in 2,3-BPG within 60 minutes, although the rise may not occur in trained athletes.

b. The P50 is also increased during exercise, because the temperature rises in active tissues and CO2 and metabolites accumulate, lowering the pH. In addition, much more O2 is removed from each unit of blood flowing through active tissues because the tissues' PO2 declines.

c. Finally, at low PO2 values, the oxygen–hemoglobin dissociation curve is steep, and large amounts of O2 are liberated per unit drop in PO2.


a. Ascent to high altitude triggers a substantial rise in 2,3-BPG concentration in red cells, with a consequent increase in P50 and increase in the availability of O2 to tissues.

b. The affinity of fetal hemoglobin (hemoglobin F) for O2, which is greater than that for adult hemoglobin (hemoglobin A), facilitates the movement of O2 from the mother to the fetus.

c. The cause of this greater affinity is the poor binding of 2,3-BPG by the polypeptide chains that replace chains in fetal hemoglobin.


a. Red cell 2,3-BPG concentration is increased in anemia and in a variety of diseases in which there is chronic hypoxia.

b. This facilitates the delivery of O2 to the tissues by raising the PO2 at which O2 is released in peripheral capillaries.

c. In bank blood that is stored, the 2,3-BPG level falls and the ability of this blood to release O2 to the tissues is reduced.

d. This decrease, which obviously limits the benefit of the blood if it is transfused into a hypoxic patient, is less if the blood is stored in citrate–phosphate–dextrose solution rather than the usual acid–citrate–dextrose solution.


a. Inosineis a nucleoside involved in the formation of purines and a compound with possible roles in energy metabolism.

b. It is a precursor to adenosine, an important energy molecule, and plays many supportive roles in the body, including releasing insulin, facilitating the use of carbohydrate by the heart, and, potentially, participating in oxygen metabolism and protein synthesis.

c. Many of the effects attributed to inosinestem from its potential role in increasing levels of a compound known as 2,3 DPG in red blood cells.

d. An enhanced 2,3 DPG level would allow an easier release of oxygen from the blood cells to the tissues.

Hypoxanthine is not mentioned in any of the available literature as having a role in increasing the 2,3 DPG level.So, by exclusion it becomes the correct answer.

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