The toxic effect of diquat on the rat lung after intratracheal administration.

Diquat toxicity to the lung was evaluated in rats. Diquat was administered intratracheally (i.t.) and its toxic potential was compared with that of paraquat. Diquat showed toxic effects in the lung when administered i.t. In previous research, diquat administered by the intravenous (i.v.) or oral (p.o.) route had little effect on the lung. a sufficient dose of diquat administered i.t. would be potentially toxic to the lung, but diquat is much less toxic to the lung than paraquat, which is actively taken up by lung tissue. This suggests that diquat is not actively taken up by lung tissue when administered i.t., but may be passively taken up by the lung tissue and induce lung damage.