A retrospective comparison of two test article vehicles commonly used in teratology studies suggested that corn oil administration during organogenesis might be associated with an increased incidence of fetal malformations (rats and mice) and reduced fetal weight (rats) as compared to administration of distilled water (Kimmel et al.. 1985). The present study examined maternal status and embryo/fetal development in timed-pregnant CD (SpragueDawley derived) rats (87-93/group) treated concurrently with DW or CO by gavage (5 ml/kg) on gestational days 6-15. Females were weighed and observed daily during treatment for clinical signs of toxicity. Maternal food and water consumption were determined throughout gestation. At sacrifice (gd 20), maternal body and liver weight, uterine weight, and the number and status of uterine implantation sites were recorded. Each live fetus was weighed, sexed, and examined for external, visceral and skeletal malformations.
No statistically significant differences were noted between groups for maternal body weight, body weight gain, liver weight or relative liver weight. Maternal food consumption (relative and absolute) was significantly depressed in the CO group relative to the DW group on gd 9-12, 12-15 and 15-20. Maternal water consumption (absolute and/or relative) was significantly depressed in the CO group on gd 6-9, 9-12, 12-15 and 15-20. No statistically significant differences between groups were noted for measures of embryo/fetal growth, viability or morphological development.
These results are in contrast to an earlier comparison of the same vehicles from historical control data. In the present study, embryo/fetal development did not differ significantly between groups of CD rats receiving corn oil (5ml/kg) or distilled water (5 ml/kg) by gavage during the period of major organogenesis.