The Core Study tested potential BPA toxicity in rodents. It also provided animals and tissues with controlled BPA doses for further study by project grantees. The strain and numbers of animals, animal diet, housing conditions, BPA doses, and route of exposure to BPA were tightly controlled. To protect the integrity of the data, CLARITY-BPA grantees were blinded to the BPA exposure levels of the animals and tissues that they received for further study.

• Pregnant Sprague-Dawley rats were orally dosed with one of three substances:
  1. BPA – 2.5, 25, 250, 2500, or 25000 micrograms per kilogram of body weight per day, to cover the wide range of BPA doses with reported effects in the scientific literature.
  2. Vehicle Control – the harmless solution used for administering BPA.
  3. Estrogen Control – 0.05 or 0.5 micrograms per kilogram of body weight per day of ethinyl estradiol, so the animals' response to a classic estrogen could be compared with response to BPA, which is suggested to have estrogen-like activity.
• The offspring were orally dosed with the same substance and dose, either daily throughout the two-year study (Continuous Dose) or daily until weaned (Stop Dose).
• For the estrogen control, the offspring were also orally dosed daily throughout the two-year study.
• NCTR staff oversaw the Core Study and collected and sent blinded tissue samples or study animals to CLARITY-BPA grantees.
• Study endpoints were examined at three timeframes: ongoing (throughout the two-year study); interim (one year); and terminal (two years).

详情请参见：https://ntp.niehs.nih.gov/whatwestudy/topics/bpa/index.html#core-study