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

The effect of hydroxychlorodiphenyl ethers (HO-ClX-DPEs; chlorinated pre- and isopredibenzodioxins), contaminants of technical chlorophenol preparations, on human erythrocyte membrane-bound adenosinetriphosphatases (ATPases) 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 concentration of these compounds, but at higher concentrations there was a gradual decrease in the extent of stimulation, 2-Hydroxy-21, 41, 41-trichlorodiphenyl ether (2-HO-Cl3-DPE; Irgasan DP-300; Triclosan) was not as effective as the nonachloro compounds at inhibiting Na+, K+, Mg2+-ATPase and was inactive at stimulating Mg2+-ATPase. Pure pentachlorophenol (PCP) caused both inhibition of Na+, K+, Mg2+-ATPase and stimulation of Mg2+-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 ATPase activities to the potent hemolytic activity of these compounds is discussed.