Effects in mice of high and low environmental temperature on the maternal and fetal toxicity of 2-sec-butyl-4,6-dinitrophenol (dinoseb) and on disposition of [14C]-dinoseb(12).

Swiss-Webster female mice were treated with 2-sec-butyl-4,6-dinitrophenol (dinoseb) and maintained in an increased environmental temperature (32 degrees C) for 24 h or a decreased temperature (0-6 degrees C) for 1.5-4 h. In two experiemtns animals maintained at low temperature were kept wet during the cold exposure, to enhance the reduction in body temperature, by rinsing them with water at approximately 30 min intervals. Results from nonpregnant females indicated that increased temperature lowered the LD50 for single injections of dinoseb from 20.2 to 14.1 mg/kg and that reduced temperature for 4 h had no effect on the LD50. A 24 h exposure to 32 degrees C enhanced the effect of 3 daily dinoseb treatments of pregnant mice; it increased maternal mortality, decreased fetal body weight, and increased frequency of fetal anomalies. Fetal body weight and the frequency of malformations were the same in groups exposed to low temperature and maintained at room temperature. Disposition of [14 C] dinoseb was also determined in nonpregnant mice exposed to temperatures of 0, 24, and 32 degrees C. The periods of environmental temperature studied (3-24 h) had no effect on the rate of disappearance of dinoseb from plasma or other tissues examined.