Immunocytochemical distribution and quantitative analysis of the Yf and Y0 subunits of glutathione S-transferase in the testis, rete testis, ductuli efferentes, and epididymis of the adult rat

The glutathione S-transferases (GSTs) are a family of isozymes that catalyze the conjugation of glutathione (GSH) with electrophiles; this function plays a protective role as the addition of GSH to an electrophile generally forms a less toxic product. The main focus of this investigation was to immunolocalize the Y$ sb{ rm f}$ and Y$ sb{ rm o}$ subunits of GST in various regions of the adult male rat reproductive system using light and electron microscopy. In the testis, Leydig cells were intensely immunoreactive for both the Y$ sb{ rm f}$ and Y$ sb{ rm o}$ subunits however, a strong reaction localized to Sertoli cells was seen only for the Y$ sb{ rm f}$ subunit. The low cuboidal epithelium of the rete testis was intensely reactive for both GST subunits however, in the ductuli efferentes, intense immunoreactivity was observed exclusively over ciliated cells immunostained for the Y$ sb{ rm f}$ subunit. Strikingly, in the corpus and proximal cauda, intense immunoreactivity was found exclusively over epithelial basal cells. The intensely stained basal cells showed extensive processes which covered most of the base of the epididymal tubule. With the electron microscope, immunogold labeling for both subunits was found randomly distributed throughout the cytoplasm and nucleus of all immunoreactive cells and was not associated with any membrane-bound organelles or nuclear structures. The strikingly different patterns of immunoreactivity for these 2 members of the GST protein family in the various cell types and regions of the tissues studied suggest they may have different functions, substrates, and/or are under different regulatory control