Impact of early exposure to DEHP phthalate on the expression and subcellular localization of the pituitary androgen receptor

Abstract

Di-2-ethylhexyl phthalate (DEHP) is a human-made compound with disruptive effects on the endocrine system. It is used in a wide variety of daily products (plastics, diapers, cosmetics) and crosses the placental barrier, affecting fetal development. Its impact on the pituitary gland and potential molecular alterations are not fully understood. The aim of this study was to analyze whether DEHP exposure during development affects the expression and localization of the pituitary androgen receptor (AR) and its impact on the gonadotroph cell population.

Pregnant rats (n=12) were randomly assigned to 2 groups: DEHP (200 µg/kg/day) and control (vehicle: corn oil), administered orally from gestation day 1 until weaning. Offspring (n=30 females and 30 males) were sacrificed on postnatal day (PND) 21 (prepubertal) or 75 (adults). The pituitary glands were processed for quantification of bLH-expressing cells (gonadotrophs) and AR by flow cytometry, for nuclear and cytoplasmic AR protein determination by western blot (WB), for identification of gonadotrophs (bLH+) and subcellular AR localization by immunofluorescence (IF). Statistical analysis was performed using ANOVA Tukey. 

In males, DEHP significantly increased the percentage of AR+ cells both at PND21 and PND75. Interestingly, in females, the effect of DEHP was similar at PND21 but opposite at PND75. In both sexes, DEHP significantly increased cytoplasmic AR expression, with a decrease in nuclear immunostaining. Furthermore, it was determined that exposure to this phthalate induces a significant increase in the gonadotroph population in both males and females at PND21, while in adulthood, a significant decrease was observed only in exposed females, with no significant changes in males.

These results demonstrate that DEHP exposure during development modifies the size of the gonadotroph population and alters the patterns of expression and subcellular localization of AR, suggesting that this phthalate affects pituitary androgenic signaling, exerting a differential effect on males and females.