Anandamide levels fluctuate in the bovine oviduct during the oestrous cycle

PLoS One. 2013 Aug 16;8(8):e72521. doi: 10.1371/journal.pone.0072521. eCollection 2013.

Abstract

Mammalian oviduct acts as a reservoir for spermatozoa and provides an environment in which they may compete for the opportunity to fertilize the oocyte. Whilst in the oviduct spermatozoa undergo capacitation essential for fertilization. Sperm-oviduct interaction is essential for sperm capacitation and is a tightly regulated process influenced by the local microenvironment. Previously we reported that the endocannabinoid anandamide (AEA) regulates sperm release from epithelial oviductal cells by promoting sperm capacitation. The aims of this work were to measure the AEA content and to characterize the main AEA metabolic pathway in the bovine oviduct and determine how these change through the oestrous cycle. In this study, the levels of AEA and two other N-acylethanolamines, N-oleoylethanolamine and N-palmitoylethanolamine, were measured in bovine oviduct collected during different stages of oestrous cycle by ultra high performance liquid chromatography tandem mass spectrometry. Results indicated that intracellular oviductal epithelial levels of all three N-acylethanolamines fluctuate during oestrous cycle. Anandamide from oviductal fluid also varied during oestrous cycle, with the highest values detected during the periovulatory period. Endocannabinoid levels from ipsilateral oviduct to ovulation were higher than those detected in the contralateral one, suggesting that levels of oviductal AEA may be regulated by ovarian hormones. The expression and localization of N-acylethanolamines metabolizing enzymes in bovine oviduct were also determined by RT-PCR, Western blot, and immunohistochemistry but no change was found during the oestrous cycle. Furthermore, nanomolar levels of AEA were detected in follicular fluids, suggesting that during ovulation the mature follicle may contribute to oviductal AEA levels to create an endocannabinoid gradient conducive to the regulation of sperm function for successful fertilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amidohydrolases / metabolism
  • Animals
  • Arachidonic Acids / metabolism*
  • Body Fluids / metabolism
  • Cattle
  • Endocannabinoids / metabolism*
  • Epithelial Cells / metabolism
  • Estrous Cycle*
  • Ethanolamines / metabolism
  • Female
  • Gene Expression Regulation
  • Intracellular Space / metabolism
  • Ovarian Follicle / metabolism
  • Oviducts / cytology
  • Oviducts / metabolism*
  • Phosphatidylethanolamines / metabolism
  • Phospholipase D / genetics
  • Phospholipase D / metabolism
  • Polyunsaturated Alkamides / metabolism*
  • Protein Transport
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism

Substances

  • Arachidonic Acids
  • Endocannabinoids
  • Ethanolamines
  • N-acylethanolamines
  • Phosphatidylethanolamines
  • Polyunsaturated Alkamides
  • RNA, Messenger
  • Phospholipase D
  • Amidohydrolases
  • fatty-acid amide hydrolase
  • anandamide

Grants and funding

This study was supported by grants from Agencia Nacional de Promoción Científica y Tecnológica (PICT N° 2010-0813), Consejo Nacional de Investigaciones Científicas y Tecnológicas (PIP 2008 2204), and Boehringer Ingelheim Fonds travel grant programme. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.