Differential disruption of gonadal development by DEHP and paracetamol in male and female Wistar rats.

Paracetamol and di(2-ethylhexyl) phthalate (DEHP) are endocrine-disrupting chemicals (EDCs) known to impair prenatal gonadal development and inhibit testosterone synthesis in experimental models. We hypothesized that these substances may interact with the endocannabinoid system (ECS), potentially contributing to testicular and ovarian developmental abnormalities. Pregnant Wistar rats were exposed to paracetamol (50 or 250 mg·kg⁻¹·day⁻¹) or DEHP (750 mg·kg⁻¹·day⁻¹) from gestational days 15-18. We assessed fetal testicular testosterone production, early postnatal ovarian follicle counts, and the expression of genes involved in steroidogenesis, testis descent, ovarian development, and ECS signaling, synthesis, and degradation. In a parallel in vitro approach, fetal rat testes from unexposed animals were incubated for three hours with paracetamol or its metabolite AM404, with or without the CB1 antagonist rimonabant. A separate group was exposed to MEHP, DEHP's main metabolite. In vivo, DEHP reduced anogenital distance and testicular testosterone in males, increased Cnr2 expression in both gonads, and upregulated Napepld in fetal testes. MEHP increased testosterone secretion in vitro. In ovaries, high-dose paracetamol reduced the number of healthy primordial and transitional follicles and increased atresia in primary and secondary follicles. DEHP exposure also elevated atresia in early-stage follicles. These findings suggest greater ovarian sensitivity to paracetamol compared to the testis.Unlike paracetamol, DEHP altered the expression of key ECS genes, suggesting a possible interplay between phthalates and the ECS. This raises the possibility that ECS components may be involved in the mechanisms of phthalate toxicity and could represent potential biomarkers, warranting further investigation.