Abstract
Effects of estradiol-17β (E2) and p-nonylphenol (NP) on the mRNA expression of sex determination-related genes were examined in the embryonic gonad of chickens. Fertilized eggs were treated with either E2 (0.1 and 1.0 mg/egg) or NP (0.001, 0.01, 0.1 and 0.2 mg/egg) twice on days 13 and 16 of incubation. The mRNA expressions of anti-Müllerian hormone (AMH), SRY-related HMG box 9 (SOX9), cytochrome P450 aromatase (P450arom) and steroidogenic factor 1 (SF-1) in the embryonic gonads were determined by the reverse transcription-polymerase chain reaction (RT-PCR) on day 18 of incubation. AMH, SOX9 and P450arom, but not SF-1, showed sexually dimorphic expression in the control ; AMH and SOX9 were male-specific while P450arom was female-specific. E2 had no significant effects on these expressions in either sex. In contrast, NP reduced the expressions of AMH and SOX9 only in the males but had no effects on the expressions of P450arom and SF-1. These results suggest that NP has endocrine disrupting effects on the mRNA expression of sex determination-related genes in the gonads of chicken embryos.
