Environmental contaminants and the HPA axis: Advances in adrenocortical hormone research in cetaceans

Abstract

Environmental pollution is one of the main threats to marine life, and chemical contaminants are known endocrine disruptors capable of altering the physiological balance of exposed organisms. Among marine mammals, cetaceans stand out as environmental sentinels due to their high trophic level, longevity, and ability to bioaccumulate lipophilic substances. This review explores the impact of environmental contamination on the hypothalamic–pituitary–adrenal (HPA) axis, a key endocrine system involved in stress responses, whose chronic dysregulation may lead to adverse health outcomes. Existing evidence suggests that environmental pollutants can interfere with the production and regulation of steroid hormones, such as glucocorticoids, aldosterone, and dehydroepiandrosterone sulfate, potentially triggering HPA axis dysfunction and prolonged stress responses. However, substantial knowledge gaps remain, particularly concerning free-ranging cetaceans, highlighting the need for integrated assessments that combine hormonal and contaminant analyses. The development and validation of non-invasive methods capable of providing physiological data without inducing additional stress are also paramount. Integrating endocrine biomarkers with ecotoxicological data may offer a comprehensive approach to assessing environmental health risks and supporting more effective conservation strategies.