Post mortem characteristics of the hepatic microsomal drug oxidising enzyme system

The stability of hepatic microsomal drug oxidation and its associated electron transport has been studied in rabbits under conditions approximating those existing prior to human autopsy. Aminopyrine N-demethylation, aniline p-hydroxylation. NADPH cytochrome c reductase, NADPH cytochrome P-450 reductase, and the microsomal content of cytochrome P-450 declined appreciably in 2 h when microsomes were prepared from rabbit liver left in situ after death. In livers removed immediately after death and kept on ice these microsomal components remained stable for at least 4.5 h. Evidence of degeneration of human microsomes prepared from liver obtained at autopsy is discussed. The lability of hepatic microsomes from livers left in situ in these experiments or prior to autopsy is most likely secondary to slow cooling of the liver with coincidental autolysis. The possibility that the degeneration observed was due to the rapid growth of bacteria was disproved. These experiments demonstrate that care must be exercised in interpreting data obtained using microsomes from human autopsy material.