Estrogenic effects of o,p′-DDT exposure in Japanese medaka (Oryzias latipes)

The persistent pesticide 1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenypethane (o,p '-DDT) has been implicated as an endocrine-disrupting chemical. In this study, we performed DNA microarray analysis to assess hepatic gene expression in male Japanese medaka (Oryzias latipes) exposed to I ppb and 100 ppb op'-DDT for 48 hr. Results showed that 1 ppb o.p'-DDT induced the expression of choriogenins (chgH, chgL, and chgH minor), and 100 ppb induced the expression of vitellogenins (vtgI and vigil) and estrogen receptor alpha. These genes showed considerably high up-regulation among the genes assayed and showed good dose-dependency. Thus, ill this study the female hormone-like endocrine-disrupting effect of o,p '-DDT at gene expression level was clearly observed in Japanese medaka.