The endocannabinoid system (ECS) is a lipid signaling system involved in numerous physiological processes, such as endocrine homeostasis, appetite control, energy balance, and metabolism. The ECS comprises endocannabinoids, their cognate receptors, and the enzymatic machinery that tightly regulates their levels within tissues. This system has been identified in various organs, including the brain and liver, in multiple mammalian and non-mammalian species. However, information regarding the sex-specific regulation of the ECS remains limited, even though increasing evidence suggests that interactions between sex steroid hormones and the ECS may ultimately modulate hepatic metabolism and energy homeostasis. Within this framework, we will review the sexual dimorphism of the ECS in various animal models, providing evidence of the crosstalk between endocannabinoids and sex hormones via different metabolic pathways. Additionally, we will underscore the importance of understanding how endocrine-disrupting chemicals and exogenous cannabinoids influence ECS-dependent metabolic pathways in a sex-specific manner.

Organophosphorus flame retardants (OPFRs) are emerging alternatives to halogenated compounds, yet their environmental toxicity remains underexplored. This study evaluated the developmental toxicity of two aryl-OPFRs, triphenyl phosphate (TPP) and tricresyl phosphate (TCP), in zebrafish (Danio rerio) from 2 h to 5 days post fertilization (hpf–dpf). Survival, hatching rate, and malformations were assessed across concentrations of 250–1000 µg/L, alongside with gene expression analysis at 5 dpf (250 and 500 µg/L) targeting detoxification (ces2), immune responses (il1β, casp9), and epigenetic markers (dnmt1, dnmt3). In vitro enzymatic assays evaluated interactions of both aryl-OPFRs with carboxylesterase (CE) and acetylcholinesterase (AChE) enzymes. While no significant morphological effects were observed, TPP showed higher toxicity than TCP. Notably, TCP (500 µg/L) downregulated genes linked to metabolism and immunity. CE activity and ces2 modulation may suggest CE as a potential biomarker for aryl-OPFR exposure. These findings, although at concentrations above the environmental ones, may be valuable for mechanistic purposes and underscore the need for further investigation in developmental toxicity given their lipophilic nature and distinct molecular responses.