Immunocytochemical localization of the Ya, Yb1, Yc, Yf, and Yo subunits ofglutathione S-transferases in the cauda epididymidis and vas deferens of adult rats

Glutathione S-transferases (GSTs) are dimeric proteins grouped into five cl asses based on the degree of amino acid homology of their subunits. They ar e involved in cellular detoxification through the catalyzation of the conju gation of reduced glutathione with various electrophilic substances. In the present study, the distribution of Ya and Yc subunits from the alpha famil y, Yb1 and Yo subunits of the mu class, and the Yf subunit of the pi class were examined with light microscope immunocytochemistry in Bouin-fixed, par affin-embedded tissue of different regions of the cauda epididymidis and va s deferens, In the cauda, principal cells showed high levels of expression of Ya, Yc, and Yo subunits, while in the vas deferens, staining decreased t o moderate levels for the Ya and Yo subunits and to low levels for the Yc s ubunit. While Yf was maintained at low levels in principal cells of ail cau da and vas deferens regions, Yb1 expression was more erratic, presenting a checkerboard-like staining pattern in the proximal vas deferens and showing moderate cytoplasmic but intense nuclear reactivity in all other regions. Basal cells in the cauda were intensely reactive for Yf, while in the vas d eferens, they became unreactive. Conversely, basal cells were unreactive fo r Ya in the cauda and proximal vas deferens, while in the middle and distal vas deferens, they became moderately reactive. In the case of Yb1 and Yo, some basal cells were reactive while others appeared unreactive in all caud a and vas deferens regions. Yc elicited the display of both reactive and un reactive basal cells in the cauda regions, and while the cells were moderat ely reactive in the proximal vas deferens, they became intensely reactive i n the middle and distal vas deferens. In summary, both principal and basal cells show varying degrees of GST expression in the different regions of th e cauda and vas deferens, suggesting that these cells are subjected to a co mplex, changing environment of substrates, Furthermore. while expression of ten differs from principal to basal cells, the absence of reactivity of a g iven GST in one cell type is usually compensated for by expression in the o ther cell type in any given region of the cauda or vas deferens. Taken toge ther, the data suggest that ample protection from harmful circulating elect rophiles can be provided for sperm during their storage in the cauda and va s deferens. In addition, since principal cells of the vas deferens are invo lved in steroid synthesis, the presence of GSTs in these cells may also ser ve to bind steroids, or this presence may be involved in steroid isomerizat ion.