EFFECTS OF ESTROGEN AND NONYLPHENOL ON THE POSTTRANSCRIPTIONAL REGULATION OF VITELLOGENIN GENE-EXPRESSION

Estrogenic chemicals have drawn considerable attention over the past s everal years because they are known to be responsible for increased br east and prostate cancer [1,2]. Vitellogenin expression driven by estr ogen has been becoming a model for studying estrogenic effects in aqua tic species. For the first time, we showed evidence that, without stim ulation, vitellogenin mRNA precursor is expressed in both male and fem ale immature fish. After 4 h, in fish treated with estradiol, the vite llogenin mRNA was synthesized and the precursor mRNA began to disappea r. The environmental chemical, nonylphenol, showed the same effect on the vitellogenin gene expression as estrogen, It is suggested that est rogen and nonylphenol may be involved in a post-transcriptional regula tion process - possibly in the initiation of pre-mRNA splicing.