Histochemical Changes in Succinic Dehydrogenase Activity in Rat Kidney Following Administration of Mercurial Diuretics

Abstract

Young, adult female rats were given subcut. injns. of Mercuhydrin (2-160 mg. Hg/kg.) and its effect on kidney succinic dehydrogenase was studied histochemically. Some animals received, in addition to Mercuhydrin, simultaneous injns. of a mercurial antagonist (BAL, l-cysteine, or glutathione). A marked and selective inhibition of enzymatic activity was observed in the cells of the proximal convoluted tubules within a few hrs. after Mercuhydrin admn. This inhibition could be completely suppressed by BAL but not by the monothiols, when given systematically. By contrast, non-selective enzymatic inhibition of all portions of the kidney was obtained when sections of normal kidneys were incubated in the neotetrazolium medium with Mercuhydrin added. Under these conditions, suppressionof the mercurial-induced enzymatic inhibition could be prevented with the monothiols as well as BAL. These studies fix the locus of mercurial action on the proximal convoluted tubule, at least insofar as the inhibition of sulfhydryl enzymes is concerned.