Effect of Pentachlorophenol on the ATPases in Rat Tissues

Abstract

The effect of pentachlorophenol (PCP) on the ATPase system in the rat hepatic, brain and kidney fractions was investigated using in vitro techniques. PCP showed a biphasic effect on oligomycin-sensitive (mitochondrial) Mg++ ATPase activities in liver and kidney tissues: at low concentrations (10−5 M) it produced stimulatory effect; at higher concentrations (10−4 M) inhibition was observed. However, in brain, only stimulation was observed at all the concentrations used. The oligomycin-insensitive Mg++ ATPase activity in liver was not altered by the addition of PCP but the brain and kidney enzyme activities were significantly inhibited. Na+, K+-ATPase in brain and kidney showed a contrasting response to PCP. A biphasic effect was seen with brain enzyme, whereas the kidney ATPase was significantly inhibited in a dose dependent manner. In addition, the In-dependent p-nitrophenyl phosphatase (K+-PNPPase) activity in rat brain microsomes was inhibited by PCP. It appears from the results that PCP may be acting as an uncoupler of oxidative phosphorylation at low concentrations and inhibiting the same at high concentrations. The results also indicate that the Na+, K+-ATPase (cation transporting enzyme) may be a locus of action of PCP.