Aim: Purification of glutathione S-transferases (GSTs) from rat testis; separation and identification of various subunits and their role in eicosanoid biosynthesis. Methods: Purification of rat testicular GSTs by affinity chromatography, employing S-hexylglutathione-linked epoxy-activated Sepharose 6B column and separation of individual subunits by reverse phase-high pressure liquid chromatography (RP-HPLC). Characterization of affinity purified GSTs by Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. The role of testicular GSTs in eicosanoid biosynthesis was determined by incubating GSTs with 5,6-Leukotriene A4Me (LTA4Me) and prostaglandin H2(PGH2) and analyzing the products formed on HPLC/TLC. Results: The present study reveals that majority of rat testicular GSTs are of Yb size (60%) with molecular weight of 27 kDa. The most predominant subunits, however, are GST Yn2 (27%), followed by GST Yc (24%) and GSTYn1 (20%). These testicular GSTs showed very high Leukotriene C4 (LTC4) synthase activity with 5,6-Leukotriene A4Me (LTA4Me) as the substrate and prostaglandin D (PGD) synthase activity with prostaglandin H2 (PGH2) as the substrate. Conclusion: Majority of rat testicular GSTs are Yb sized and are involved in the synthesis of eicosanoids like LTC4 and PGD2.

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