Avian vitreous humor concentrations of inosine, hypoxanthine, xanthine, uric acid, uracil and uridine as influenced by age and sex: their relevance as indicators of ante-mortem hypoxia.

An investigation was made to determine the effects of age and sex on postmortem concentrations (mumol/l) of inosine, hypoxanthine, xanthine, uric acid, uracil and uridine in the vitreous humor of chickens (Gallus domesticus). Five male and 5 female chickens were sampled each week from 0-10 weeks of age. Samples were collected at 0 and 24 h postmortem and analysed by HPLC. Hypoxanthine, uric acid and uridine were detected at both 0 and 24 h postmortem whereas inosine, xanthine and uracil were detected only at 24 h postmortem. Neither sex nor the sex X age interaction influenced the concentrations of the compounds investigated (P greater than 0.01). Age had a significant influence on the concentrations of all compounds at 24 h postmortem (P less than 0.0001). At 0 h postmortem, age significantly affected the levels of hypoxanthine and uridine (P less than 0.0001) but not uric acid (P = 0.014). All compounds occurred at higher concentrations at 24 than 0 h postmortem with the exception of uridine at 0 and 1 week of age. Previous studies using data confounded by age and postmortem sampling time have concluded that postmortem vitreous humor hypoxanthine concentration is a useful indicator of antemortem hypoxia. The results of this study cast doubt on that conclusion. Age and postmortem sampling time should be rigorously controlled when conducting quantitative analyses of these compounds in vitreous humor.