Utilization of citrate and lactate through a lactate dehydrogenase and ATP-regulated pathway in boar spermatozoa

Incubation of boar spermatozoa in Krebs–Ringer–Henseleit medium with either 10 mM lactate or 10 mM citrate induced a fast and robust increase in the intracellular levels of ATP in both cases, which reached a peak after 30 sec of incubation. Utilization of both citrate and lactate resulted in the exp...

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Published in:Molecular reproduction and development Vol. 73; no. 3; pp. 369 - 378
Main Authors: Medrano, Antonio, Fernández-Novell, Josep Ma, Ramió, Laura, Alvarez, Juan, Goldberg, Erwin, Montserrat Rivera, Ma, Guinovart, Joan J., Rigau, Teresa, Rodríguez-Gil, Joan E.
Format: Journal Article
Language:English
Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-03-2006
Wiley-Liss
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Summary:Incubation of boar spermatozoa in Krebs–Ringer–Henseleit medium with either 10 mM lactate or 10 mM citrate induced a fast and robust increase in the intracellular levels of ATP in both cases, which reached a peak after 30 sec of incubation. Utilization of both citrate and lactate resulted in the export of CO2 to the extracellular medium, indicating that both substrates were metabolized through the Krebs cycle. Incubation with citrate resulted in the generation of extracellular lactate, which was inhibited in the presence of phenylacetic acid. This indicates that lactate is produced through the pyruvate carboxylase step. In addition, there was also a significant increase in tyrosine phosphorylation induced by both citrate and lactate. Boar sperm has a sperm‐specific isoform of lactate dehydrogenase (LDH), mainly located in the principal piece of the tail. Kinetic studies showed that boar sperm has at least two distinct LDH activities. The major activity (with an estimated Km of 0.51 mM) was located in the supernatants of sperm extracts. The minor LDH activity (with an estimated Km of 5.9 mM) was associated with the nonsoluble fraction of sperm extracts. Our results indicate that boar sperm efficiently metabolizes citrate and lactate through a metabolic pathway regulated by LDH. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Bibliography:ark:/67375/WNG-MP0XRR4K-6
istex:07DD29E17D8FCEEA019441C6E9A913E5030944A3
Ministry of Science and Technology, Spain - No. AGL2001-2568
ArticleID:MRD20414
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:1040-452X
1098-2795
DOI:10.1002/mrd.20414