Uptake of diflubenzuron (N-[[(4-chlorophenyl)amino] carbonyl]-2,6-difluorobenzamide) by rat C6 glial cells in vitro

The uptake, subcellular localization, and metabolic fate of [¹⁴C]diflubenzuron, N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide, in cultured rat C6 glial cells have been characterized. Confluent monolayer cultures display a concentration-dependent uptake of the labeled insecticide. Experiments conducted in the presence and absence of dimethyl sulfoxide (DMSO) showed that 1.2% DMSO in the growth medium had no significant effect on the rate of incorporation of radioactivity. Diflubenzuron was not metabolized to any measurable extent and more than 98% of the administered compound could be recovered from whole cells and the culture medium by extraction with diethyl ether. As much as 95% of the cell-associated radioactivity was localized in the particulate fraction. Pulse-chase experiments revealed that less than 10% of the [¹⁴C]diflubenzuron incorporated during 24 hr of incubation was released into the growth medium over a period of 48 hr. This study in conjunction with our previous investigation (A. C. Stoolmiller, Gen. Pharmacol. 9, 11, 1978) indicates that diflubenzuron is neither cytotoxic nor does it inhibit the synthesis of complex carbohydrates in animal cells.