Postmortem vitreous hypoxanthine measurement is used as a supplement to vitreous potassium for TSD estimation. Hypoxanthine is a product of:

• A Postmortem protein catabolism via the urea cycle
• B Haemoglobin breakdown forming biliverdin and iron
• C Oxidation of vitreous lactate by lactate dehydrogenase
• D Purine nucleotide degradation from ATP → ADP → AMP → IMP → inosine → hypoxanthine ✓

Explanation

Following cessation of oxidative phosphorylation, ATP degrades sequentially to ADP, AMP, then inosine monophosphate (IMP) via AMP deaminase, then inosine, and finally hypoxanthine via nucleoside phosphorylase. Hypoxanthine thus accumulates postmortem in vitreous humor in a time-dependent manner, complementing vitreous potassium for TSD estimation, particularly in the early postmortem period. The other options describe unrelated catabolic pathways.

Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.