In present work, some biochemical characteristics of the catfish, Clarias gariepinus were studied under
the effect of different sublethal doses of 4-nonylphenol (0, 0.05, 0.08 and 0.1 mgl-1). Liver enzymes ALT
and AST increased insignificantly at P<0.05 whereas the ALP decreased insignificantly. The activities of
G6PDH showed significant increase with the increased sublethel doses of 4-nonylphenol while the
activities of LDH decreased insignificantly with increase of such doses. The concentrations of serum
glucose and total cholesterol significantly increased after exposure to 4-nonylphenol, although
Hyperglycemia is evident. The kidney function parameters such as total serum protein and uric acid
increased insignificantly after exposure to 4-nonylphenol in comparison with the control fish whereas
creatinine exhibited significant increase (P<0.05). Some serum ions decreased significantly (HCO3
- and
Na+) or insignificantly (Cu+2, Cl- and Ca+2) and others increased significantly (Fe+2) or insignificantly (K+)
under 4-nonylphenol stress on C. gariepinus. Increased serum anion gap was associated with
increased hyperglycemia and insignificant hypocalcemia. Such increased gap referred to nonylphenolinduced
metabolic acidosis. The adverse impact of the sublethal doses of 4-nonylphenol on the
molecular structure of the protein was evident by electrophoresis. In conclusion, in addition to its
tissue-specific estrogenic effects, 4-nonylphenol has non-estrogenic adverse effects on liver and
kidney functions through activation of other metabolism-related genes distinct from estrogenresponsive
genes.