Influence of 2-deoxy-D-glucose and energy substrates on guinea-pig sperm capacitation and acrosome reaction

Abstract

When guinea-pig spermatozoa were suspended in a minimal culture medium (MCM-PL), 2-deoxy-D-glucose (100 microM) and 2-amino-2-deoxy-D-glucose (100 microM) were potent inhibitors of the acrosome reaction without affecting the sperm motility, whereas the N-acetyl derivative 2-acetamido-2-deoxy-D-glucose (2 mM) had no inhibitory effect. The addition of D-glucose (2 mM) partly inhibited the percentage acrosome reaction of spermatozoa suspended in Medium MCM-PL, but DL-alpha-glycerophosphate (2 mM) and myo-inositol (2 mM) had no effect. In addition, DL-alpha-glycerophosphate (2 mM) did not overcome the inhibitory effect of 2-deoxy-D-glucose on the sperm acrosome reaction. The inhibitory action of 2-deoxy-D-glucose (100 microM) on the sperm acrosome reaction assessed after a 3-h incubation was irreversible and was only completely effective if the sugar was added within 30 min of the start of incubation. When spermatozoa suspended in Medium MCM-PL were treated with 2-deoxy-D-glucose (100-200 microM) for an extended incubation up to 6 h, the inhibitory effect of 2-deoxy-D-glucose was partly overcome. Spermatozoa treated with 2-deoxy-D-glucose had significantly reduced concentrations of ATP after incubation for 2 h in Ca2+-free media, compared with the ATP concentrations of spermatozoa preincubated for 2 h in Ca2+-free media that supported acrosome reactions. The addition of Ca2+ (5 mM) caused a rapid decrease in ATP concentrations of spermatozoa suspended in Medium MCM-PL, while the addition of the monovalent ionophore monensin (50 microM) and Ca2+ stimulated sperm acrosome reactions as well as an additional decline in the sperm ATP concentrations. However, monensin (50 microM) in the absence of Ca2+ caused only a slight decline in the sperm ATP concentrations over the 15-min incubation period. The depletion of the sperm ATP concentrations by 2-deoxy-D-glucose may retard completion of the capacitation process and the resultant acrosome reaction.

Glycolysis plays an important role in energy transfer from the base to the distal end of the flagellum in mouse sperm

“…1C). Similar results were obtained when glycolysis was inhibited by 2-deoxy-D-glucose (DOG), an analog of glucose that inhibits hexokinase (Hiipakka and Hammerstedt, 1978; Hyne and Edwards, 1985) (data not shown). Because sliding velocity was known to correlate with ATP concentration (Yano and Miki-Noumura, 1980;Si and Okuno, 1995), these results indicated a decrease in intracellular ATP by ACH even in the presence of respiratory substrates.…”

Glucose is a pH-Dependent Motor for Sperm Beat Frequency during Early Activation

“…2DG is a structural glucose analog which is taken up by glucose transporters (GLUT) [29], of which GLUT8, GLUT9a and GLUT9b have been shown to localize to the acrosome and the tail of murine sperm [30], [31], [32]. Indeed, 2DG is phosphorylated by hexokinase to 2DG-phosphate but it cannot be further metabolized by glucose-6-phosphate dehydrogenase or phosphohexoisomerase, thus inhibiting glycolysis [33], [34]. In the presence of 2DG, basal sperm beat frequency of ∼3.5 Hz declined significantly after 10 min which is in agreement with data of Mukai and Okuno [35].…”

Bioenergetics of Mammalian Sperm Capacitation

“…Glucose was also required for capacitation in hamster [32] and may also be necessary for optimal capacitation in macaque sperm [33]. In contrast, glucose inhibited capacitation in guinea pig [34], bovine [35] and dog sperm, where in vitro capacitation is carried out in a medium without this hexose [36]. …”