AbstractThe incorporation of radioactive diisopropyl phosphorofluoridate (DF32P) in the subcellular fractions of rat liver cells has been studied when injected alone or followed or preceded by pyridine‐2‐aldoxime methane sulphonate (P28), N,N'‐trimethylene‐bis‐(pyridinium‐4‐aldoxime) (TMB‐4) and atropine. In experiments with only DF32P the total labelled phosphorus (32P) incorporated in the liver as well as the amounts taken up in the microsomal and mitochondrial fractions attain a maximum value in 20 min, but there is a considerable readjustment of32P between the nuclear and supernatant fractions even at 60 min. The oximes administered prophylactically or therapeutically affect both the rate of uptake of DF32P and the quantity incorporated. The effects are explained on the basis of the rate of penetration of DF32P in the cell and possible direct action of the oximes. Atropine has a high retarding effect on the uptake of DF32P in the liver, the total quantity incorporated being reduced to 5–10% of the control in