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ZFIN ID: ZDB-PUB-080902-1
An investigation into the role of prostaglandins in zebrafish oocyte maturation and ovulation
Lister, A.L., and Van Der Kraak, G.
Date: 2008
Source: General and comparative endocrinology 159(1): 46-57 (Journal)
Registered Authors: Van Der Kraak, Glen
Keywords: zebrafish, reproduction, prostaglandins, cyclooxygenase, ovulation
MeSH Terms:
  • Animals
  • Arachidonic Acid/pharmacology
  • Cyclooxygenase 1/genetics
  • Cyclooxygenase 1/metabolism
  • Cyclooxygenase 2/genetics
  • Cyclooxygenase 2/metabolism
  • Dose-Response Relationship, Drug
  • Female
  • Gene Expression Regulation, Developmental/drug effects
  • Group IV Phospholipases A2/genetics
  • Group IV Phospholipases A2/metabolism
  • Indomethacin/pharmacology
  • Oogenesis/genetics
  • Oogenesis/physiology*
  • Ovarian Follicle/drug effects
  • Ovarian Follicle/metabolism
  • Ovulation/genetics
  • Ovulation/physiology*
  • Prostaglandin-Endoperoxide Synthases/genetics
  • Prostaglandin-Endoperoxide Synthases/metabolism
  • Prostaglandins/metabolism
  • Prostaglandins/physiology*
  • Prostaglandins E/metabolism
  • Prostaglandins E/physiology
  • Prostaglandins F/metabolism
  • Prostaglandins F/physiology
  • Radioimmunoassay
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tissue Culture Techniques
  • Zebrafish/genetics
  • Zebrafish/physiology*
PubMed: 18722378 Full text @ Gen. Comp. Endocrinol.
This study explored the potential for ovarian-derived prostaglandins (PGs) to be involved in the regulation of oocyte maturation and ovulation in zebrafish. It was demonstrated that cultured vitellogenic follicles have the capacity to produce prostaglandin E(2) (PGE(2)) and PGF(2alpha) in response to arachidonic acid (AA) in a concentration-dependent manner, and that AA stimulates the in vitro production of 17beta-estradiol (E(2)). The production of AA-stimulated PGF(2alpha) was significantly reduced by treatment with the non-selective cyclooxygenase (COX) inhibitor, indomethacin (INDO). Treatment of full-grown follicles with AA did not induce oocyte maturation as assessed by germinal vesicle breakdown, but INDO significantly decreased the rate of spontaneous maturation. Using Real-Time PCR, it was shown that follicles of different developmental size classes (primary growth and pre-vitellogenic, early-vitellogenic, and mid- to full-grown vitellogenic) express enzymes that release (cytosolic phospholipase A(2) (cPLA(2)); phospholipase Cgamma1) or metabolize (COX-1, COX-2, and prostaglandin synthase-2) AA to PG metabolites. The expression of cPLA(2) was found to be significantly greater in full-grown follicles compared to follicles of the pre- and early-vitellogenic stages. In vivo studies demonstrated that breeding groups of zebrafish exposed to 100mug/L INDO exhibited reduced spawning rates and clutch sizes compared with control and 1mug/L INDO exposed fish. In other studies, it was shown that naturally spawning groups of females exhibit increased ovarian levels of PGF(2alpha), E(2), and 17alpha,20beta-dihydroxy-4-pregnen-3-one (a maturation-inducing hormone in zebrafish) near the time of ovulation compared with non-breeding females. Collectively, these experiments indicate that the AA pathway in zebrafish ovaries is involved in the regulation of oocyte maturation and ovulation and a non-selective inhibitor of COX disrupts these processes.