Regional variation in human extracellular purine levels

Area of Science:

• Biochemistry
• Neuroscience
• Cardiovascular Physiology

Background:

• Purine deoxynucleosides exhibit selective toxicity to lymphocytes.
• Extracellular purines modulate neurotransmission and coronary blood flow.

Purpose of the Study:

• To accurately measure extracellular purine nucleoside and hypoxanthine-xanthine levels in human biological fluids.
• To investigate potential sources of plasma purines.

Main Methods:

• Utilized a sensitive fluorimetric assay for purine measurement.
• Collected blood and cerebrospinal fluid specimens with adenosine deaminase inhibitors.
• Analyzed purine levels in arterial blood, venous blood, cerebrospinal fluid, and bone marrow aspirates.

Main Results:

• Normal peripheral venous plasma purine levels averaged 2.7 +/- 1.2 microM, with adenosine (38%) and hypoxanthine-xanthine (47%) as major components.
• Arterial hypoxanthine-xanthine levels were lower than mixed venous levels (p < 0.005).
• Bone marrow aspirates displayed 10-fold higher hypoxanthine-xanthine levels compared to venous plasma.
• Cerebrospinal fluid showed elevated hypoxanthine-xanthine and lower adenosine levels compared to venous blood.

Conclusions:

• Bone marrow is a potential major source of plasma purines.
• Distinct purine profiles exist in different human biological compartments.
• Accurate measurement of extracellular purines is feasible and provides insights into physiological processes.