Effects of phenolic compounds on 5-nucleotidase activity in some tissues of Notopterus notopterus (Pallas): a biochemical study.

In the present study, effects of phenol (P), 2,4-dinitrophenol (DNP) and pentachlorophenol (PCP) individually, and in three combinations viz., (PCP + DNP)/P (highly antagonistic), (DNP + P)/PCP (additive) and (P + DNP)/PCP (highly synergistic) at three sublethal levels (1/10, 1/15, and 1/20 fractions of 96 h LC50) on 5-nucleotidase activity have been studied in brain, liver, kidney and gills of a freshwater teleost, Notopterus notopterus. The results indicate that 5-nucleotidase activity was inhibited significantly (P less than 0.05; P less than 0.01; P less than 0.001) in these tissues at most of the concentrations after 15 and 30 days of exposure. However, significant stimulation (P less than 0.05) of this enzyme was also notice in kidney at 1/20 of P, and (PCP + DNP)/P combination after 15 days of exposure. Inhibition of this enzyme in tissues possibly represents the uncoupling of oxidative phosphorylation, while stimulation of the enzyme indicates that the concerned phenolic compounds might be inducing the cells of the kidney to produce more of this enzyme.