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.
Propylene glycol, a common solvent used in industry, food, and in consumer goods, 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, 1.0, 2.5, 5.0% PG in drinking water. These concentrations produced calculated consumption estimates of nearly equal to 1.819, 4.796, and 10.118 g/kg body weight/d.
Although water consumption in the F0 generation was consistently higher for all groups (by 6 to 15%), these increases were not statistically different from controls. There was no effect on body weights during either the continuous cohabitation portion of the study. All groups had greater than or equal to 4.6 litters/pair, with greater than or equal to 11.9 pups/litter. There was no treatment-related effect on pup weight adjusted for litter size (control value: 1.55 g). The viability and growth of the final litter was unaffected by PG consumption.
Since there was no effect on fertility, a Task 3 crossover was not conducted. At the time this study was conducted, the protocol called for no necropsy of F0 animals in the absence of a fertility effect, so the F0 mice were killed and discarded without necropsy.
For the second generation, just the control and 5% PG groups were evaluated. There was no treatment-related effect on mating, fertility, or on the number, weight, or viability of the F2 offspring.
After delivery of the F2 pups, the F1 adults were killed and necropsied. There was no effect on body or organ weights in males or females, no change in sperm endpoints, and no change in estrous cycle parameters. Serum total calcium levels were measured in serum of the F1 mice, and was found unchanged by PG exposure from a control value of 9.2 mg/dL.
In summary, propylene glycol, under the conditions of this experiment, has no effect on fertility and reproduction in either generation of Swiss mice at up to 10 g/kg/day.