DEVELOPMENTAL TOXICITY STUDY IN FISCHER-344 RATS BY WHOLE-BODY EXPOSURE TO N,N-DIMETHYLETHANOLAMINE VAPOR

Timed-pregnant Fischer 344 rats were exposed whole body to N,N-dimethy lethanolamine vapor for 6 h per day on gestational days 6-15 at mean ( +/- SD) analytically measured concentrations of 10.4 +/- 0.86, 29.8 +/ - 2.14 and 100 +/- 4.9 ppm, Darns were sacrificed on gestational day 2 1, There was no maternal mortality in any exposed groups, Maternal tox icity observed in the 100 ppm group included reduced body weight durin g and after exposures, reduced weight gain during exposure and ocular changes (darkened, cloudy and hazy eyes, slight corneal vascularizatio n and fixed, dilated pupils), Ocular effects were also noted in the ot her two exposure groups; the effects were quite marked at 30 ppm but o nly minimal and transient at 10 ppm, There were no effects of treatmen t on any gestational parameters, including pre- and postimplantation l oss or sex ratio, Fetal body weights per litter were statistically sig nificantly increased at 100 ppm relative to controls, There were no in creases in the incidences of total malformations by category (external , visceral or skeletal) or individually, The incidence of six skeletal variations out of 120 noted differed in exposed groups relative to th at of control, Four of these variations were decreases in incidence; o nly one fetal variation, the split (bipartite) cervical centrum, was e levated at 100 ppm relative to controls, In the absence of any other i ndications of delayed ossification or fetal body weights, the observed fetal variation does not suggest a consistent pattern of fetal toxici ty, Hence, the no-observed-adverse-effect level is around 10 ppm for m aternal toxicity and at or above 100 ppm for embryofetal toxicity and teratogenicity.