Published-Ahead-of-Print November 28, 2007, DOI:10.2164/jandrol.107.003533
Journal of Andrology, Vol. 29, No. 4, July/August 2008
Copyright © American Society of Andrology
DOI: 10.2164/jandrol.107.003533
Adenosine Triphosphate Production by Bovine Spermatozoa and Its Relationship to Semen Fertilizing Ability
LOUISE J. A. GARRETT*,
STUART G. REVELL
AND
HENRY J. LEESE*
From the * Department of Biology, University of
York, York, United Kingdom; and the
Genus
Freezing Unit, Llanrhydd, Ruthin, United Kingdom.
|
Correspondence to: Dr Henry J. Leese, Department of Biology, University of
York, York YO10 5YW, United Kingdom (e-mail:
hjl1{at}york.ac.uk). |
This article's objectives are to investigate the relationship between
adenosine triphosphate (ATP) production (oxidative phosphorylation and
glycolysis) and fertility of bovine spermatozoa, determine the proportion of
oxygen consumption devoted to proton leak and that due to nonmitochondrial
processes, and discover whether freeze/thawing affects sperm oxygen
consumption. Oxygen consumption of bovine spermatozoa was measured using a
standard Clark electrode and, for the first time, in an Oxygen Biosensor
System (OBS). Total ATP formation by bovine spermatozoa was calculated from
the oxygen consumption and lactate production (glycolysis) by the same
spermatozoa sample. ATP production varied from 1.99 to 8.09 µmol ATP per
108 spermatozoa per hour; glycolysis accounted for 16% to 38% of
ATP. Nonmitochondrial oxygen consumption could not be detected in bovine
spermatozoa using these methods. A significant proportion (16%–43%) of
oxygen consumption was insensitive to oligomycin and was due to "proton
leak." There was no significant difference between oxygen consumption of
frozen/thawed and fresh spermatozoa for 2 of the 3 bulls tested. However,
oxygen consumption of frozen/thawed spermatozoa was significantly higher (P
< .05) than fresh spermatozoa for the third bull. When ZO2 of
frozen/thawed spermatozoa from 20 bulls was compared with their 49 day
nonreturn rates (NRRs), oxygen consumption was correlated positively with NRR
(ie, fresh spermatozoa with a higher ZO2 were more fertile).
Moreover, total ATP production correlated with NNR better than ZO2.
Bulls with a lower NRR produce spermatozoa that are susceptible to damage
during the freeze/thawing process, causing an increase in ZO2,
possibly due to mitochondrial membrane damage resulting in more energy being
expended in maintaining the proton gradient, or capacitation-like changes
causing hyperactivation. Oxygen consumption measured in the OBS may be useful
in assessing bovine sperm fertility.
Key words: Fertility, semen analysis, sperm, oxygen consumption
Copyright © 2008 by The American Society of Andrology.