An article published on May 29, 2017 in the peer-reviewed Journal of Applied Toxicology investigated the influence of a phthalate, diethylhexyl phthalate (DEHP, CAS 117-81-7), on the accumulation of bisphenol A (BPA, CAS 80-05-7) in the tissues of mice. Evan Borman and colleagues from the Department of Psychology, Neuroscience & Behaviour, McMaster University, Ontario, Canada, injected male and female mice with different concentrations of DEHP. 30 minutes later, radioactively labeled BPA (14C-BPA) was delivered orally with peanut butter. Accumulated concentrations of 14C-BPA in different tissues were measured one hour later.
In cycling females and peri-implantation females, DEHP significantly increased 14C-BPA deposition in the uterus, ovaries, and blood serum compared to controls not exposed to DEHP. In the former group, significantly higher accumulation in the muscle tissue was also observed. In DEHP-exposed males, higher accumulation of 14C-BPA was observed in the epididymis and blood serum.
These data are consistent with the hypothesis that DEHP and BPA may compete for detoxification capacity, for example through the phase II enzyme EDP-glucuronosyltransferase. The findings reported here also help explain the previous observation reported by the same group in December 2016. In that study, combined administration of DEHP and BPA caused a reduction in blastocyst implantation in inseminated female mice at doses below those necessary for DEHP or BPA individually to induce the same effect.
Previous studies have shown similar effects of other commonly used chemicals, triclosan (CAS 3380-34-5), butyl paraben (CAS 94-26-8), and propyl paraben (CAS 94-13-3), all of which were shown to enhance BPA accumulation upon co-administration (FPF reported). The authors suggest that the effects of concurrent exposure to multiple chemicals should be taken into account when regulatory exposure limits are being determined.
Borman, E., et al. (2017). “Diethylhexyl phthalate magnifies deposition of 14C-bisphenol A in reproductive tissues of mice.” Journal of Applied Toxicology (published May 29, 2017).
Borman, E., et al. (2017). “Concurrent administration of dethylhexyl phthalate reduces the threshold dose at which bisphenol A disrupts blastocyst implantation and cadherins in mice.” Environmental Toxicology and Pharmacology 49:105-111.