Does thermal stress modulate the biochemical and physiological responses of Ruditapes decussatus exposed to the progestin levonorgestrel?

In this study, we investigated the effects of 1000 ng/l levonorgestrel (LNG) alone or combined with increased temperature of 20, 24, and 28 °C on the biochemical and physiological responses of the clam (Ruditapes decussatus) for 28 days. Our results revealed that female clams treated with levonorgestrel (LNG) alone showed enhancement of the antioxidant defense against oxidative stress related to the inductions of catalase (CAT), gluthatione -S -transferase (GST), and protein sulfhydryl (PSH), while the elevated temperatures of 20, 24, and 28 °C diminished most of the specific responses to LNG and was the main factor in the determining the responses to combine exposures. The responses of lysosomal membrane stability, alkaline phosphatase, and NADP-dependent isocitrate dehydrogenase detected were the most common signs of an adverse effect in all exposures. Female clams' testosterone and estradiol responses to LNG were the most particular manifestations depending on the exposure. Overall, these findings showed clearly that chronic warming stress caused disruption in physiological, biochemical parameters of the female clam R. decussatus, and this may have implications for the whole organism and populations.