197 DIFFERENTIAL EFFECTS OF FLUTAMIDE AND DI-(2-ETHYLHEXYL) PHTHALATE ON MALE REPRODUCTIVE ORGANS IN A RAT MODEL
T. T. B. Vo A , E.-M. Jung A , M.-G. Back A , V. H. Dang A , K.-C. Choi A B and E.-B. Jeung AA Laboratory of Veterinary Biochemistry and Molecular Biology, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea;
B Department of Obstetrics and Gynecology, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
Reproduction, Fertility and Development 21(1) 197-197 https://doi.org/10.1071/RDv21n1Ab197
Published: 9 December 2008
Abstract
Endocrine disruptors (EDs) with androgenic and anti-androgenic effects may alter reproductive function by binding to androgenic receptors (AR) and inducing or modulating AR-dependent responses in the male reproductive system. However, the molecular mechanism(s) underlying these events remains unclear. Thus, in the present study, we elucidated the prenatal effects of maternal testosterone propionate (TP), flutamide (Flu), and di-(2-ethylhexyl) phthalate (DEHP) on male reproductive organs of newborn rats. Pregnant Sprague-Dawley (n = 32 in total, n = 8/each group) rats were treated with these compounds at gestation days 11 to 21, and newborn males (n = 154 in total) were euthanized at post-neonatal day (PND) 63. Interestingly, maternal exposure to Flu or DEHP caused fluctuations in the neonatal levels of serum testosterone (T) and luteinizing hormone (LH). Serum T and LH were up-regulated by Flu, but these hormones were down-regulated by DEHP. The anogenital distances (AGD) of male newborns were detected at PND 1, 21, and 63. Male rats treated prenatally with DEHP (100 mg kg–1 mother’s body weight) or Flu showed an AGD shorter than that of control rats. At PND 63, the sperm concentration, viability, and mobility were reduced in the maternal DEHP and Flu-treated groups. The numbers of seminiferous tubules were reduced in the Flu- and DEHP-treated offspring when compared with vehicle- and TP-treated groups, and the tubules of the testes at PND 63 were disrupted by a high dose of Flu. In addition, we examined differential gene expression patterns in the testes by microarray analysis following ED exposure, particularly in sex determination-related genes. Significantly distinct expressions of sex determination-related genes were observed in the testes by microarray analysis following treatments with different types of EDs in this study. Although Flu and DEHP are considered to be identical with regard to their anti-androgenic effects, their effects on developing male reproductive organs were distinct, suggesting that Flu competes with endogenous T, while DEHP influences a different step in androgenesis.
