Abstract

The sublethal impacts of nonylphenol ethoxylates (NPE) on glucose metabolism and endocrine disruption in Clarias gariepinus were examined. Exposure to sublethal concentrations of NPE (0.50, 0.75, 1.00, and 1.25 mg/L) induced alterations in glucose levels and corticosteroid secretion. Blood samples for glucose were obtained from the caudal vein and analysed by the glucose oxidase method, while cortisol levels were assessed using enzyme-linked immunosorbent assay (ELISA) in accordance with the manufacturer’s protocol. Initially, glucose levels rose after two days, followed by a marked decrease as exposure continued, with significant alterations noted on day 30 (p < 0.05), except for the 0.05 mg/L treatment (p < 0.05). The initial increase in glucose is associated with glucose serving as the principal energy source and a marker of stress response. Cortisol levels rose with time in all treatment groups, exhibiting statistically significant differences (p < 0.05; p < 0.01). The findings indicate that NPE functions as an endocrine disruptor, elevating glucose levels and altering hormonal balances. This suggests that NPE exposure could have comparable impacts on human health, possibly resulting in lethal outcomes. Given that the majority of NPE exposure arises from human activities, it is imperative for authorities to enforce more stringent measures to mitigate the associated hazards.

Key words: Nonylphenol ethoxylates, Clarias gariepinus, Hydrocortisone, Glucose, Plasma