Distribution of  -glutamyl transpeptidase in the mouse epididymis and its response to acivicin

Abstract

Summary. \g=g\-Glutamyltranspeptidase (\g=g\-GT), its substrate (GSH) and hydrolytic product (l-glutamic acid) were measured biochemically in mouse reproductive tissues. The epididymal caput and seminal vesicles showed the highest specific activities of \g=g\-GT, while GSH and l-glutamic acid were widely distributed in all tissues. Histochemically, \g=g\-GTdisplayed a strong apical and supranuclear reaction and a moderate basal activity in the ductuli efferentes, a weak luminal reaction in the first, a moderate apical reaction in the second and a strong apical and supranuclear reaction in the third segment of the epididymal caput. In the epididymal corpus and cauda, the \g=g\-GT reaction was confined to the tubular lumina but an apical reaction was also present in the cauda. The daily administration of acivicin (12 mg/kg body weight), an irreversible inhibitor of \g=g\-GT, for 14 days resulted in a 60% suppression of the enzyme activity in the epididymal caput, while the \g=g\-GT inhibition in the kidney was >95%. The treatment caused no change in the activity of alanyl aminopeptidase. Histochemically, the basal and supranuclear \g=g\-GT activities in the ductuli efferentes and the third epididymal segment were suppressed, but the apical reactions were maintained. The in-vivo suppression of epididymal \g=g\-GTactivity may have implications in the control of post-testicular sperm maturation.

Structure and function of the ductuli efferentes: A review

“…The distribution of 8-glutamyl transpeptidase in the mouse epididymis was examined recently (Agrawal et al, 1989). It was found that the activity of this enzyme was exhibited strongly in the epithelium of the ductuli efferentes and was localized both in supranuclear and basal locations.…”

“…Histochemical localizations of various glycoconjugates (Agrawal et al, 1989) and enzymes (Burkett et al, 1987a,b;Byers and Graham, 1990;Cohen et al, 1976; have inferred secretions of glycoconjugates and amino acids from the epithelium destined for sperm coating and ions in connection with absorption and acid-base balance. Also, structural studies in various animals also have shown granules and apical blebs and protrusions in the nonciliated cells which have the appearance of being extruded or secreted into the lumen (Bakst, 1980;Goyal and Hrudka, 1981;Gray et al, 1983;Hess and Bassily, 1988;Wystub et al, 1989).…”

Gamma GlutamylTranspeptidase Activity Determination in Epididymis of Corynorhinusmexicanus Bat Throughout Its Annual Cycle

“…As mentioned before, GGT is present in the epididymis, mainly in the head region [13], being the high catalytic activity of GGT in proximal epididymal region, and decreases in the distal region [14,15]. In the present study, it was found that GGT activity is high in the cephalic region, on dates in which sperm are present in the epididymis, something equivalent to what was reported in rat, where they found that GGT concentration was low in immature rats and increased in sexual maturity of rats.…”

“…The catalytic activity of GGT is highest in the proximal epididymal regions and decreases toward the distal regions [14,15].…”

Growth Factor-Stimulated Mitogen-Activated Kinase (MAPK) Phosphorylation in the Rat Epididymis Is Limited by Segmental Boundaries1

“…A recent development relevant to how different parts of the epididymis play specific biological roles has been the realization that the anatomical, intraregional segments of the epididymis are likely to be functional units within the organ [4,5]. Experiments using tracer molecules have shown that diffusion in the interstitium between segments is severely restricted by the CTS [4], and it has been shown that the regionalization of biologically relevant properties of the epididymal duct, such as protein and gene expression, often coincide exactly with the limits imposed by the CTS [4,[6][7][8][9][10]. These observations have led to the hypothesis that segmentation of the epididymal interstitium by the CTS provides a physiological basis for epithelial segmental function by creating tightly controlled interstitial microenvironments within different epididymal segments.…”