Pyrethroids are synthetic insecticides that have replaced organochlorine pesticides in the last decades. The effects of two pyrethroids (cypermethrin and permethrin) on plasma metabolites levels, hypothalamus-pituitary-interrenal axis and growth axis in juveniles of Senegalese sole Solea senegalensis were studied. The 24 h and 72 h LC50 values of cypermethrin and permethrin for Solea senegalensis were 500 µg L-1 and 900 µg L-1, respectively. The specimens were divided into 5 experimental groups exposed to: i) ethanol vehicle in water (control), ii) exposure to 1/25 value of cypermethrin LC50 (20 µg L-1) (in ethanol), iii) exposure to 1/10 value of cypermethrin LC50 (50 µg L-1), iv) exposure to 1/25 value of permethrin LC50 (36 µg L-1), and v) exposure to 1/10 value of permethrin LC50 (90 µg L-1). Sublethal exposure to cypermethrin and permethrin significantly lowered plasma glucose, lactate and triglycerides levels, while total soluble proteins increased significantly. In cypermethrin treated fish, corticotrophin-releasing factor (CRF) gene expression enhanced significantly with the low dose; while neither doses of permethrin altered this expression. However, both insecticides increased plasma cortisol levels. Cypermethrin and permethrin enhanced insulin-like growth factor (IGF-I) expression but decreased PACAP expression at both doses. This study indicated that both pyrethroids (cypermethrin and permethrin) insecticides enhanced stress and inhibited growth axes.
Pyrethroid, Toxicity, Fish, Hormone, Neuropeptide, Gene