In vivo effect of mercuric chloride on tissue ATPases of Notopterus notopterus.

Effect of sublethal concentrations, 0.088, 0.044, 0.029, 0.022 and 0.0176 mg HgCl2 per liter (1/5, 1/10, 1/15, 1/20, and 1/25 fractions of 96-h LC50) on Na+-K+, Mg2+, and total ATPase activities in brain, gills, kidney and liver of Notopterus notopterus have been studied after 30 days exposure. Na+-K+ ATPase were inhibited maximally and significantly in brain and minimally and insignificantly in liver. Mg2+ ATPase was inhibited maximally and significantly (P less than 0.01) in brain and minimally and insignificantly in kidney. The relative inhibition of total, Na+-K+ and Mg2+ ATPases for the tissues studied were brain greater than gill greater than kidney greater than liver. At the concentration (1/25 fraction) the enzyme activity returned to the normal range.