Renal cortical mercury distribution following dithiothreitol administration

Abstract

Previous studies from this laboratory have indicated that dithiothreitol (DTT) administration (31 mg DTT/kg, i.p.) 1 h after mercuric chloride injection (3 mg/kg, i.v.) results in partial reversal of Hg‐lnduced renal toxicity without altering total renal mercury deposition. Studies were performed, therefore, to determine if DTT administration altered the renal delivery, excretion, and/or, in particular, subcellular distribution of mercury in a way that may explain the observed phenomenon. Analysis of mercury partitioning between red cells and plasma revealed no difference in relative distribution when Hg‐ or Hg + DTT‐treated groups were compared. However, absolute mercury concentration in both whole blood and plasma of Hg + DTT‐treated rats was significantly higher than in the Hg‐treated group. Total urinary excretion of mercury was significantly less in Hg + DTT‐treated rats than in rats treated with mercury alone. The subcellular distribution of mercury in the paniculate and supernatant fractions of renal cortical homogenates from Hg‐treated and Hg + DTT‐treated rats was similar. Fractionatlon of the supernatant on G‐75 Sephadex gel revealed no difference In the protein profiles between the Hg‐ and Hg + DTT‐treated groups. It is concluded that DTT administration ameliorates the nephrotoxic effect of prior mercury injection by a more subtle mechanism than redistribution of renal cortical mercury.