Developmental Toxicity Evaluation of Inhaled Nitrobenzene in CD Rats

Developmental Toxicity Evaluation of Inhaled Nitrobenzene inCD Rats. TYL, R. W., FRANCE, K. A., FISHER, L. C., DODD, D.E., PRITTS, I. M, LYON, J. P., O'NEAL, F. O., and KIMMERLE,G. (1987). Fundam. Appl. Toxicol. 8, 482–492. PregnantCD (Sprague–Dawley) rats were exposed to nitrobenzenevapor (CAS Registry No. 98-95-3) at 0, 1, 10, and 40 ppm (meananalytical values of 0.0, 1.06, 9.8, and 39.4 ppm, respectively)on gestational days (gd) 6 through 15 for 6 hr/day. At sacrificeon gd 21, fetuses were evaluated for external, visceral, andskeletal malformations and variations. Maternal toxicity wasobserved: weight gain was reduced during exposure (gd 6–9and 6–15) to 40 ppm, with full recovery by gd 21, andabsolute and relative spleen weights were increased at 10 and40 ppm. There was no effect of treatment on maternal liver,kidney, or gravid uterine weights, on pre- or postimplantationloss including resorptions or dead fetuses, on sex ratio oflive fetuses, or on fetal body weights (male, female, or total)per litter. There were also no treatment-related effects onthe incidence of fetal malformations or variations. In summary,during organogenesis in CD rats, there was no developmentaltoxicity (including teratogenicity) associated with exposureto nitrobenzene concentrations that produced some maternal toxicity(10 and 40 ppm) or that produced no observable maternal toxicity(1 ppm).