Some effects of dieldrin and mirex on Ehrlich ascites tumor cells in vivo and in vitro.

The effects of dieldrin and mirex on Ehrlich ascites tumor cells were assessed, using certain in vivo (in mice) and in vitro measurements. Mirex retarded the development of Ehrlich ascites tumor in vivo, but dieldrin did not. Effects of dieldrin on de nova RNA purine synthesis from formate in vivo were slight, while mirex inhibited the synthesis of both RNA purines. Dieldrin inhibited the in vitro incorporation if thymidine, uridine, and L-leucine into DNA, RNA, and protein, respectively, but mirex was virtually without effect.