Alterations in neurotransmitters, steroid hormones, vitellogenin, and antioxidant system induced by di-n-butyl phthalate and di-isopentyl phthalate on catfish Rhamdia quelen.

Phthalates, such as di-n-butyl phthalate (DBP) and di-isopentyl phthalate (DiPeP), are pollutants with a high potential for endocrine disruption. This study aimed to evaluate parameters of endocrine disruption in specimens of the Neotropical fish Rhamdia quelen exposed to DBP and DiPeP through their food. After 30 days of exposure, the fish were anesthetized and then euthanized, and blood, hypothalamus, liver, and gonads were collected. DBP caused statistically significant alterations in the serotoninergic system of males (5 and 25 ng/g) and females (5 ng/g) of R. quelen and it increased testosterone levels in females (25 ng/g). DiPeP significantly altered the dopaminergic system in females, reduced plasma estradiol levels (125 ng/g) and hepatic vitellogenin expression (25 ng/g), and changed the antioxidant system in gonads (125 ng/g). The results suggest that DBP and DiPeP may have different response patterns in females, with the former being androgenic and the latter being anti-estrogenic. These findings provide additional evidence regarding the molecular events involving DBP and DiPeP in the endocrine disruption potential in juvenile specimens of Rhamdia quelen.