The influence of temperature rise on the metabolic response of Ruditapes philippinarum clams to 17-?-ethinylestradiol

Untargeted Nuclear Magnetic Resonance metabolomics was employed to study the effects of warming conditions (17-21 degrees C) and exposure to 17-alpha-ethinylestradiol (EE2) on the polar metabolome of Ruditapes philippinarum clams, to identify metabolic markers for monitoring/prediction of deviant environmental conditions. Warming alone trig-gered changes in alanine/aspartate/glutamate, aromatic amino acids, taurine/hypotaurine and homarine/trigonelline pathways, as well as in energy metabolism, suggesting osmoregulatory adaptations and glycolytic/tricarboxylic acid (TCA) cycle activation, possibly accompanied to some extent by gluconeogenesis to preserve glycogen reserves. At 17 degrees C, the lowest EE2 concentration (5 ng/L) specifically engaged branched-chain and aromatic amino acids to activate the glycolysis/TCA cycle. Notably, a partial metabolic recovery was observed at 25 ng/L, whereas higher EE2 concen-trations (125 and 625 ng/L) again induced significant metabolic disturbances. These included enhanced glycogen bio-synthesis and increased lipid reserves, sustained by low-level glutathione-based antioxidative mechanisms that seemed active. At 21 degrees C, response to EE2 was notably weak at low/intermediate concentrations, becoming particularly significant at the highest EE2 concentration (625 ng/L), suggesting higher protection capacity of Ruditapes philippinarum clams under warming conditions. At 625 ng/L, disturbances in alanine/aspartate/glutamate and tau-rine/hypotaurine metabolisms were observed, with no evidence of enhanced carbohydrate/protein catabolism. This low energy function profile was accompanied by marked antioxidative mechanisms and choline compounds modula-tion for cell membrane protection/repair. These results help monitor clams ' response to temperature rise and EE2 ex-posure, paving the way for future effective guidance and prediction of environmental damaging effects.