title: Di-(2-ethylhexyl) phthalate and mono-(2-ethylhexyl) phthalate inhibit growth and reduce estradiol levels of antral follicles in vitro.
abstract: Any insult that affects survival of ovarian antral follicles can cause abnormal estradiol production and fertility problems. Phthalate esters (PEs) are plasticizers used in a wide range of consumer and industrial products. Exposure to these chemicals has been linked to reduced fertility in humans and animal models. Di-(2-ethylhexyl) phthalate (DEHP) and mono-(2-ethylhexyl) phthalate (MEHP) decrease serum estradiol levels and aromatase (Arom) expression, prolong estrous cycles, and cause anovulation in animal and culture models. These observations suggest PEs directly target antral follicles. We therefore tested the hypothesis that DEHP (1-100 microg/ml) and MEHP (0.1-10 microg/ml) directly inhibit antral follicular growth and estradiol production. Antral follicles from adult mice were cultured with DEHP or MEHP, and/or estradiol for 96 h. During culture, follicle size was measured every 24 h as a measurement of follicle growth. After culture, media were collected for measurement of estradiol levels and follicles were subjected to measurement of cylin-D-2 (Ccnd2), cyclin-dependent-kinase-4 (Cdk4), and Arom. We found that DEHP and MEHP inhibited growth of follicles and decreased estradiol production compared to controls at the highest doses. DEHP and MEHP also decreased mRNA expression of Ccnd2, Cdk4, and Arom at the highest dose. Addition of estradiol to the culture medium prevented the follicles from DEHP- and MEHP-induced inhibition of growth, reduction in estradiol levels, and decreased Ccnd2 and Cdk4 expression. Collectively, our results indicate that DEHP and MEHP may directly inhibit antral follicle growth via a mechanism that partially includes reduction in levels of estradiol production and decreased expression of cell cycle regulators.
authors.affiliation: Division of Toxicology, Department of Veterinary Biosciences, University of Illinois, Urbana-Champaign, IL, USA.
authors.forename: Rupesh K
authors.initials: RK
authors.lastname: Gupta
authors.forename: Jeffery M
authors.initials: JM
authors.lastname: Singh
authors.forename: Tracie C
authors.initials: TC
authors.lastname: Leslie
authors.forename: Sharon
authors.initials: S
authors.lastname: Meachum
authors.forename: Jodi A
authors.initials: JA
authors.lastname: Flaws
authors.forename: Humphrey H-C
authors.initials: HH
authors.lastname: Yao
mesh_terms: D000818:Animals; D001483:Base Sequence; D002455:Cell Division / Q000187:drug effects*; D017931:DNA Primers; D004051:Diethylhexyl Phthalate / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D051379:Mice; D006080:Ovarian Follicle / Q000187:drug effects* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D017931:DNA Primers; D012333:RNA, Messenger; D004958:Estradiol; D004051:Diethylhexyl Phthalate; C016599:mono-(2-ethylhexyl)phthalate