O 22. Differential expression of the Wnt/β - catenin pathway in the genital tubercle (GT) of fetal male rat following maternal exposure to di-n-butyl phthalate (DBP)

Di-n-butyl phthalate (DBP) is one of the most abundantly produced endocrine disruptors that leaches out from polyvinyl chloride plas-tics and can cause hypospadias in male rats during maternal exposure. The objective of this study was to first explore the roles of Wnt/β-catenin pathway in the fetal rat genital tubercle (GT) following in-utero exposure to DBP. Timedpregnant rats were given DBP by gastric intubation at a dose of 750 mg/kg body weight (bw)/day from gestation day (GD) 14 to (GD) 18 to establish a rat model of hypospadias. On (GD) 19, genital tubercle down-regulation of β-catenin, Phospho- GSK-3β, andup-regulation of GSK-3β (glycogen synthase kinase-3β), NFκB in fetal male rats was observed by western blot analysis. β-catenin was located in the urethral plate epithelium (UPE). Immunochemistry showed that the relative expression of β-catenin decreased in the DBP-trea-ted fetal rat GT compared to the normal control. These findings, for the first time, indicate that DBP may affect the development of GT by down-regulating the Wnt/β-catenin pathway in fetal male rats.