EFFECT OF ALTERATION OF RAT HEPATIC MIXED-FUNCTION OXIDASE (MFO) ACTIVITY ON TOXICITY OF 2,3,7,8-TETRACHLORODIBENZO-PARA-DIOXIN (TCDD)

The effect of alteration of the activity of the hepatic mixed-function oxidase (MFO) enzyme systems on the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in rats has been examined. These experiments have indicated the naturally occurring age and sex-related differences in hepatic MFO activity in rats are inversely correlated with the 20-day LD50 of TCDD in these animals. The effect of administering inducers and inhibitors of the hepatic MFO enzyme systems on the 20-day LD50 of TCDD in rats has also been examined. In all cases there was an inverse relationship between the activity of the hepatic MFO system at the time of TCDD administration and the toxicity of TCDD as determined by the 20-day LD50. © 1978.