Effect of Freezing and Thawing Process on the Capacity of Malate-Aspartate Shuttle of Boar Spermatozoa

Nishimura, Kazuhiko

doi:10.1262/jrd.38.6_j71

Cited by 1 publication

(4 citation statements)

References 11 publications

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“…These results coincide with previous findings [17,18]. However, depletion of Ca 2+ ions by EGTA caused an increase in L:P upon addition of ethanol; this suggests that the capacity of the malate-aspartate shuttle decreased.…”

Section: Discussionsupporting

confidence: 92%

“…It has been reported that the motility of spermatozoa is related to ATP:ADP and to the level of ATP [17,18,31]. In the present experiments there was a correlation between L:P, which reflects the redox state of the cytosol, and ATPADP, which reflects the energy level (Fig.…”

Section: Correlation Between Lp and Atp:adpsupporting

confidence: 68%

“…The capacity of the malate-aspartate shuttle is related to mitochondrial function [17][18][19][20] and to the motility of spermatozoa [17,18] as confirmed in Figure 4.…”

Section: Discussionmentioning

confidence: 73%

“…Cytosolic NADH cannot traverse the mitochondrial membranes, so the reducing equivalents of cytosolic NADH are transferred to the mitochondria by shuttle systems. Previous studies [17,18] have shown that the capacity of the malate-aspartate shuttle is closely related to the ratio of ATP to ADP (ATP:ADP) in boar spermatozoa, suggesting that an assessment of the capacity of the malateaspartate shuttle may be useful for the evaluation of damage to mitochondrial membranes by freezing and thawing of boar spermatozoa. The malate-aspartate shuttle of rat liver is activated by Ca 2 + ions [19].…”

Section: Introductionmentioning

confidence: 99%

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Effects of Calcium Ions on the Malate-Aspartate Shuttle in Slow-Cooled Boar Spermatozoa

Nishimura¹

1993

Biology of Reproduction

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The effects of intracellular free calcium (Ca2+) ions on the malate-aspartate shuttle were studied in slow-cooled boar spermatozoa. The capacity of the malate-aspartate shuttle was assessed by an indirect method on the basis of accumulation of lactate relative to pyruvate when ethanol is provided as substrate. The capacity of the malate-aspartate shuttle at 37 degrees C was dependent on the presence of Ca2+ ions and was stimulated by an influx of Ca2+ ions induced by the combination of the Ca2+ ionophore A23187 and 100 microM CaCl2. When washed spermatozoa were cooled slowly to 15 degrees C, the percentage of progressive motile spermatozoa was about half that at 37 degrees C in 100 microM Ca(2+)-containing medium, while the capacity of the malate-aspartate shuttle remained equal to that at 37 degrees C. The motility decreased further at higher concentrations of Ca2+ ions. Spermatozoa in EGTA-containing medium barely moved at 15 degrees C and the capacity of the malate-aspartate shuttle decreased. Even in Ca(2+)-containing medium, LaCl3 caused a decrease in the capacity of the malate-aspartate shuttle at 15 degrees C. These results suggest that an influx of a low concentration of Ca2+ ions activates the malate-aspartate shuttle at 15 degrees C, with a subsequent increase in the proportion of cells that maintain progressive motility.