Pyridoxal phosphate concentrations determined postmortem as an indication of antemortem vitamin B-6 status

In anticipation of studies relating vitamin B-6 status determined at autopsy to known pathologic causes of death, the postmortem stability of pyridoxal phosphate (PLP) in the plasma, skeletal muscle, and liver of pigs was assessed. Concentrations of plasma K, Mg, Na, and Ca also were examined for postmortem stability using the pig as an experimental model. At 1 hr after death, the mean plasma PLP concentration was essentially unchanged from that observed prior to death. Thereafter, plasma PLP concentration increased with increasing postmortem time interval and was 2.3 times greater than initial by 6 hr postmortem and 7.6 times greater than initial by 12 hr postmortem (P less than 0.01). Skeletal muscle and liver PLP content were 35% lower than initial by 6 hr postmortem (P less than 0.01). Plasma K and Mg were significantly higher by 1 hr postmortem (P less than 0.01) while plasma Na concentration was significantly lower by 1 hr postmortem (P less than 0.01). Plasma Ca concentration was not significantly different at any measured time point. Knowledge of the postmortem time interval appears to be required in order to evaluate the antemortem vitamin B-6 status using pyridoxal phosphate values derived from autopsy samples.