Effects of the anti-androgen cyproterone acetate (CPA) on oocyte meiotic maturation in rainbow trout (Oncorhynchus mykiss).
In the present study, we aimed at characterizing the effect of cyproterone acetate (CPA), an anti-androgenic compound, on oocyte meiotic maturation in a freshwater teleost fish species, the rainbow trout (Oncorhynchus mykiss). Fully-grown post-vitellogenic ovarian follicles were incubated in vitro with CPA, luteinizing hormone (Lh) or a combination of CPA and Lh. Incubations were also performed using a combination of Lh and testosterone (T). The occurrence of oocyte maturation (i.e., resumption of the meiotic process) was assessed by monitoring germinal vesicle breakdown (GVBD) after a 72h in vitro incubation. The effect of CPA on the production of 17,20β-dihydroxy-4-pregnen-3-one (17,20βP), the natural maturation-inducing steroid (MIS), was quantified by radioimmunoassay. Our results show that CPA dramatically inhibits Lh-induced oocyte maturation and MIS synthesis. We also observed a synergistic effect of Lh and T on oocyte maturation in highly competent oocytes (i.e., able to resume meiosis after stimulation by low doses of Lh). Our results also show that a combination of CPA and Lh inhibits phosphorylation of extracellular signal-regulated kinase (Erk), kinases that are associated with oocyte maturation in many species. As a whole, our results indicate that CPA has a potential to alter meiotic maturation in rainbow trout. Further analyses are, however, needed to determine the mechanisms by which this anti-androgen interferes with the meiotic process. Furthermore, the present study provides a framework for better understanding of the ecological consequences of exposure to anti-androgens and resulting meiotic maturation abnormalities observed in trout.
INRA, UR1037 Fish Physiology and Genomics, Sex Differentiation and Oogenesis Group, F-35000 Rennes, France. Electronic address: helene.rime@rennes.inra.fr.
Hélène
H
Rime
INRA, UR1037 Fish Physiology and Genomics, Sex Differentiation and Oogenesis Group, F-35000 Rennes, France.
Thaovi
T
Nguyen
INRA, UR1037 Fish Physiology and Genomics, Sex Differentiation and Oogenesis Group, F-35000 Rennes, France.
Kevin
K
Ombredane
INRA, UR1037 Fish Physiology and Genomics, Sex Differentiation and Oogenesis Group, F-35000 Rennes, France.
Alexis
A
Fostier
INRA, UR1037 Fish Physiology and Genomics, Sex Differentiation and Oogenesis Group, F-35000 Rennes, France.
Julien
J
Bobe
D000726:Androgen Antagonists / Q000494:pharmacology / Q000633:toxicity; D000818:Animals; D017373:Cyproterone Acetate / Q000633:toxicity*; D005260:Female; D006908:Hydroxyprogesterones / Q000378:metabolism; D007986:Luteinizing Hormone / Q000378:metabolism; D008540:Meiosis / Q000187:drug effects; D017686:Oncorhynchus mykiss / Q000254:growth & development / Q000502:physiology*; D009865:Oocytes / Q000187:drug effects*; D006080:Ovarian Follicle / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity
D000726:Androgen Antagonists; D006908:Hydroxyprogesterones; D014874:Water Pollutants, Chemical; C007433:17,20-dihydroxy-4-pregnen-3-one; D017373:Cyproterone Acetate; D007986:Luteinizing Hormone
Cyproterone acetate; Erk family; Fish; Gene expression; Meiosis; Oocyte; Reproduction