Effect of hydroxychlorodiphenyl ethers (chlorinated pre‐and isopredioxins) on erythrocyte membrane adenosinetriphosphatase activity

Abstract

The effect of hydroxychlorodiphenyl ethers (HO‐Cl_x‐DPEs; chlorinated pre‐ and isopredibenzodioxins), contaminants of technical chlorophenol preparations, on human erythrocyte membrane‐bound adenosinetriphosphatases (A TPases) has been investigated. Both 2‐ and 3‐HO‐Cl₉‐DPE inhibited the Na⁺+K⁺‐activated, Mg²⁺‐dependent ATPase (Na⁺,K⁺,Mg²⁺‐ATPase). The Mg²⁺‐dependent ATPase (Mg²⁺‐ATPase) was stimulated at lower concentrations of these compounds, but at higher concentrations there was a gradual decrease in the extent of stimulation. 2‐Hydroxy‐2’,4,4 ‐trlchlorodiphenyl ether (2‐H0‐Cl₃‐DPE; Irgasan DP‐300; Triclosan) was not as effective as the nonachloro compounds at inhibiting Na⁺, K⁺, Mg²⁺‐A TPase and was inactive at stimulating Mg²⁺‐A TPase. Pure pentachlorophenol (PCP) caused both inhibition of Na⁺,K⁺,Mg²⁺‐ATPase and stimulation of Mg‐ATPase, although each effect required a higher concentration of PCP than was needed for the HO‐Cl₉‐DPEs. The possible relationship of the effects of HO‐Cl_x‐DPEs on human erythrocyte membrane A TPase activities to the potent hemolytic activity of these compounds is discussed.