Evaluation of the estrogenic activities of some pesticides and their combinations using MtT/Se cell proliferation assay

A number of pesticides are used in agricultural production with some having estrogenic activities, such as endocrine-disrupting chemicals that may affect wildlife and humans. This study aimed to detect the estrogenic effects of some mixed agricultural chemicals in agricultural production. The assay to measure estrogenic activity was evaluated by the cell proliferative activity of MtT/Se cells, which respond well to estrogen. To evaluate MtT/Se cells we went down to the molecular level of estrogen receptor (ER)-α and ER-β expression. The proportion of ER-α to ER-β was 3.55:1, as determined by semi-quantitative real-time PCR. These results showed that ER-α was dominant in MtT/Se cells on the transcriptional level, therefore implying that the estrogenic activity detected by these cells may be mainly mediated by ER-α. It was found that diazinon, tolclofos–methyl, pyriproxyfen, prothiofos and thiabendazole had estrogenic activity. Several pesticides are often present in agricultural products. Therefore, we evaluated the estrogenic activity of a mixture of two pesticides. The REC10 levels of prothiofos/pyriproxyfen and thiabendazole/orthophenylphenol were increased up to 10-fold. We concluded that those two pesticide combinations showed a significantly higher estrogenic effect in comparison to the results of the respective pesticides when tested individually.