The following abstract presents results of a study conducted by a contract laboratory for the National Toxicology Program. The findings were not evaluated in accordance with the levels of evidence for reproductive or developmental criteria established by NTP in March 2009. The findings and conclusions for this study should not be construed to represent the views of NTP or the U.S. Government.
Triethylene Glycol (TG) was tested for reproductive toxicity in Swiss CD-1 mice using the RACB protocol. It was part of a series of glycol ethers and congeners evaluated for structure-activity correlations using this design. Data collected on body weights, clinical signs, and food/water consumption during the dose-range-finding segment (Task 1) were used to set concentrations for the main study (Task 2) at 0.0, 0.3, 1.5%, and 3.0% in the drinking water. These concentrations gave calculated consumption estimates of 0.6, 3.3, and 6.8 g/kg/d.
Two animals died in the control, middle dose group, and high dose group. TG consumption had no effect on the number of litters/pair delivered during Task 2, nor the number of live pups/litter. The mean live pup weight adjusted for litter size was reduced in the 1.5% and the 3.0% groups by 4% and 4.5%, respectively.
The lack of change in the number of pups/litter or number of litters/pair led to the decision not to conduct Task 3 (the crossover mating to determine the affected sex).
For the second generation, only the control and high dose groups were evaluated. For the week before mating, when fluid consumption was measured, the treated mice consumed nearly equal to 16% more fluid than the controls. Nonetheless, there was no effect on the ability of the treated animals to mate or to deliver a litter of pups. Those litters had as many live pups as the controls, and the pups weighed the same (i.e., adjusted pup weight was not reduced by TG exposure).
The F1 mice were killed and necropsied after the F2 pups were delivered and evaluated. Relative liver weight was increased by 5% and 6% in males and females, but there were no changes in body weight or other organ weights at necropsy in males or females. Epididymal sperm concentration, motility, and morphology were unaffected by TG exposure at 3%.
In summary, TG was not a reproductive toxicant in either generation of Swiss mice when administered in drinking water at concentrations of up to 3% w/v, although developmental toxicity was noted in the first generation as reduced pup body weight.