View source for Sugimura 2012 J Reprod Dev

{{Publication
|title=Sugimura S, Matoba S, Hashiyada Y, Aikawa Y, Ohtake M, Matsuda H, Kobayashi S, Konishi K, Imai K. (2012) Oxidative phosphorylation-linked respiration in individual bovine oocytes. J Reprod Dev 58:636-41.
|info=[http://www.ncbi.nlm.nih.gov/pubmed/22785440 PMID: 22785440 Open Access]
|authors=Sugimura S, Matoba S, Hashiyada Y, Aikawa Y, Ohtake M, Matsuda H, Kobayashi S, Konishi K, Imai K.
|year=2012
|journal=J Reprod Dev
|abstract=Mitochondrial bioenergetics in mammalian oocytes has not been sufficiently characterized. In this study, the function of oxidative phosphorylation (OXPHOS), a major pathway in mitochondria, was investigated in individual bovine oocytes by monitoring oxygen consumption using modified scanning electrochemical microscopy (SECM). At the germinal vesicle (GV) stage, 65% of basal respiration was used for mitochondrial respiration, which was inhibited by complex IV inhibitor. Around 63% of mitochondrial respiration was coupled to ATP synthesis, as determined by sensitivity to an ATP synthase inhibitor, and the remaining 37% was attributed to proton leak. In contrast, 50% and 43% of mitochondrial respiration were used for ATP synthesis in ''in vivo''- and ''in vitro-derived'' metaphase II (MII)-stage oocytes, respectively. ATP-linked respiration, in both ''in vivo''- and ''in vitro-derived'' MII-stage oocytes, was significantly lower than in GV-stage oocytes, suggesting that OXPHOS in bovine oocytes is more active at the GV stage compared with the MII stage. Interestingly, basal respiration in ''in vitro-derived'' MII oocytes was significantly higher than for ''in vivo-derived'' oocytes, reflecting an increase in proton leak. Next, we assessed respiration in MII oocytes cultured for 8 h. The aged oocytes had a significantly reduced maximum respiratory capacity, which was stimulated by a mitochondrial uncoupler, and reduced ATP-linked respiration compared with non-aged oocytes. However, the aging-related phenomenon could be prevented by caffeine treatment. We conclude that OXPHOS in bovine oocytes varies in the transition from GV to MII stage, ''in vitro'' maturation and the aging process. This approach will be particularly useful for analyzing mitochondrial bioenergetics in individual mammalian oocytes.
|keywords=Bovine, Mitochondrial function, Oocyte, Oxidative Phosphorylation, Oxygen consumption
}}
{{Labeling
|area=Respiration, Developmental biology
|diseases=Aging;senescence
|organism=Bovines
|tissues=Genital
|preparations=Intact cells
|couplingstates=LEAK, ROUTINE, ET
}}