Abstract:

OBJECTIVE: To explore the effects of di-(2-ethylhexyl) phthalate (DEHP) on protein expression of hormonal-related genes including 3β-hydroxysteroid dehydrogenase (3β-HSD), gonadotropin-releasing hormone receptor (GnRHR), follicle-stimulating hormone receptor (FSHR) and luteinizing hormone receptor (LHR) in rats. METHODS:A total of 80 5-week-old male and female Sprague-Dawley rats were randomly divided into four groups with 20 rats in each group. The DEHP doses were 0 mg/kg in control group (corn oil), 100 mg/kg in low dose group, 500 mg/kg in medium dose group and 1 500 mg/kg in high dose group. Rats were exposed to DEHP via gavage administration for consecutive six weeks, DEHP administration was once a day and five times a week. After the exposure, rats were anesthetized through ether, then sacrificed for the further studies. The protein expressions of 3β-HSD, GnRHR and FSHR in testis and ovary was analyzed by Western blot. RESULTS:Compared with control group, the expression of 3β-HSD protein was significantly increased in DEHP 500 and 1 500 mg/kg groups ( P<0.01), GnRHR was decreased in DEHP 1 500 mg/kg group (P<0.01), FSHR was decreased in DEHP 500 and 1 500 mg/kg groups (P<0.05 or P<0.01, respectively). The protein expressions of LHR in DEHP 500 and 1 500 mg/kg groups were decreased by 25% to 35% when compared with control, whilst GnRHR protein expressions were decreased by 60% to 80% in DEHP 500 and 1 500 mg/kg groups (P<0.05 or P<0.01). CONCLUSION:DEHP could cause endocrine disorder and interfere with the synthesis of sex hormones in rats, ultimately leading to male and female reproductive dysfunction.

Key words: di-(2-ethylhexyl) phthalate, β-hydroxysteroid dehydrogenase, gonadotropin-releasing hormone receptor, follicle-stimulating hormone receptor, luteinizing hormone receptor, reproductive toxicity