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Y. Agrawal and T. Vanha-Perttula

Summary. Particles found in bovine seminal vesicle secretion were enriched by centrifugation. They varied in size and morphology and contained Mg2+,Ca2+-activated ATPase, aminopeptidase A, alanyl aminopeptidase, γ-glutamyl transpeptidase and dipeptidyl peptidase IV activities. Hyperactivation of sperm motility and the acrosome reaction were induced by these particles in epididymal spermatozoa suspended in a modified Ringer medium. The hyperactivation, analysed with a microscopic slide test, started within minutes of exposure to membrane particles and continued for 3–4 h, during which time spermatozoa underwent the acrosome reaction. Acrosome staining, phase-contrast microscopy and transmission electron microscopy revealed that the acrosome reaction started within 60 min at 37°C and affected up to 80% of spermatozoa in 4 h. These membrane particles differed from those reported previously in other species in enzyme composition, function and organ of origin.

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Y. P. Agrawal, T. Peura and T. Vanha-Perttula

Summary. γ-Glutamyl transpeptidase (γ-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 γ-GT, while GSH and l-glutamic acid were widely distributed in all tissues. Histochemically, γ-GT displayed 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 γ-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 γ-GT, for 14 days resulted in a 60% suppression of the enzyme activity in the epididymal caput, while the γ-GT inhibition in the kidney was >95%. The treatment caused no change in the activity of alanyl aminopeptidase. Histochemically, the basal and supranuclear γ-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 γ-GT activity may have implications in the control of post-testicular sperm maturation.

Keywords: γ-glutamyl transpeptidase; acivicin; mouse; epididymis