Histochemical Localization of Some Dehydrogenase Enzymes in the Bull Testis and Epididymis

Abstract

The distribution and relative activities of succinate, lactate, glucose-6-phosphate, malate, glutamate, and β-hydroxybutyrate dehydrogenases have been histochemically evaluated in the normal adult bull testis and caput epididymis. In the seminiferous tubule, the spermatogonial cells appear to display fairly high levels of activity in most of the enzymes investigated but, except for glutamate and β-hydroxybutyrate dehydrogenases, there was a marked decrease of activity in the older spermatocytes and spermatids. Sertoli cells showed a virtual absence of enzymatic activity. Leydig cells showed very high concentrations of enzymes, particularly glucose-6-phosphate, malate, and lactate dehydrogenase. Other enzymes were not very reactive in these cells, and could not be demonstrated in the remainder of the interstitium. Lactate, glucose-6-phosphate, and succinate dehydrogenase showed fairly strong activity in the epithelial cells of a portion of the caput epididymis. The surrounding muscle cells and connective tissue gave very weak reactions for all enzyme substrates tested. Spermatozoa in both tubular and epididymal lumina showed the presence of some dehydrogenases, all activity being confined to the mid-piece section of these cells.