Abstract

A spectrophotometric investigation of the interaction and coordination of lead compounds with glutathione (GSH) in lymphocytes of healthy male volunteer venous blood has been described. The present study was designed to provide insight into the proposed mechanism of action of lead acetate {Pb(CH₃COO)₂} and lead acetylacetonate (C₁₀H₁₄O₄Pb) with GSH at molecular level. Lymphocytes were separated from blood of healthy human volunteers. Different concentrations of lead acetate and lead acetylacetonate were used and their concentration, time, pH and temperature dependent effects on GSH level was studied. Ellman’s method was used for the determination of GSH. With lead compounds, a decreased concentration of GSH was found, which further decreased with increasing concentration of lead compounds. A more decrease in GSH concentration was found with time-dependent (0-90 minutes) incubation of lymphocytes with lead compounds. pH, 8.5 and temperature, 45°C have been found to be most favorable for reactions of lead compound with GSH. It may be suggested that changes in GSH status produced by lead compounds could be due to the formation of conjugates (Pb-SG) between GSH and lead compounds or conversion of GSH to oxidized GSH (GSSG) in lymphocytes. The interaction and coordination of lead compounds with sulphur suggest the sulfhydryl (-SH) group to be the coordinating site of GSH.

Key words: Glutathione (GSH), 5-5- dithiobis 2-nitrobenzoic acid (DTNB, Ellman’s reagent), metapfosphoric acid (MPA), lead acetate, lead acetylacetonate (LAA), lymphocytes.