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

Antonio Medrano, Josep Ma Fernández-Novell, Laura Ramió, Juan Alvarez, Erwin Goldberg, Ma Montserrat Rivera, Joan J. Guinovart, Teresa Rigau, Joan E. Rodríguez-Gil*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)369-378
Number of pages10
JournalMolecular reproduction and development
Volume73
Issue number3
DOIs
StatePublished - Mar 1 2006

Keywords

  • Boar spermatozoa
  • Citrate
  • Energy metabolism
  • LDH
  • Lactate

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology
  • Cell Biology

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