Involvement of estrogens in the process of sex differentiation in two fish species: The rainbow trout (Oncorhynchus mykiss) and a Tilapia (Oreochromis niloticus): The rainbow trout (Oncorhynchus mykiss) and a Tilapia (Oreochromis niloticus)

Y Guiguen, J F Baroiller, M J Ricordel, K Iseki, O M McMeel, Samuel Allen Moore Martin, A Fostier

Research output: Contribution to journalArticle

233 Citations (Scopus)

Abstract

In order to study the physiological implication of sex steroid hormones in gonadal sex differentiation in fish, we first investigated the potential role of estrogens using two fish models: the rainbow trout (Oncorhynchus mykiss) and a tilapia species (Oreochromis niloticus). All experiments were carried out on genetically all-male (XY) and all-female (XX) populations. In vivo treatments with an aromatase inhibitor (ATD, 1,4,6- androstatriene3-17-dione) result in 100% masculinization of an all-female population in rainbow trout (dosage 50 mg/kg of food) and 75.3% in tilapia (dosage 150 mg/kg of food). In tilapia, the effectiveness of the aromatase inhibition by ATD is demonstrated by the marked decrease of the gonadal aromatase activity in treated animals versus control. No masculinization is obtained following treatment with an estrogen receptor antagonist (tamoxifen) in both species. Aromatase and estrogen receptor gene expression was studied in rainbow trout by semi-quantitative RT-PCR in gonads sampled before, during and after sex-differentiation. Aromatase mRNA is specifically detected in female gonads, 3 weeks before the first sign of histological sex-differentiation, i.e., first female meiosis. Aromatase expression in male gonads is at least a few hundred times less than in female gonads. Estrogen receptor gene is expressed in both male and female gonads at all stages with no dimorphic expression between sexes. Specific aromatase gene expression before ovarian differentiation was also demonstrated using virtual Northern blot, with no expression detected in male differentiating gonads. From these results it can be concluded that estrogen synthesis is crucial for ovarian differentiation, and transcription of the aromatase gene can be proposed as a key step in that process in fish. (C) 1999 Wiley-Liss, Inc.

Original languageEnglish
Pages (from-to)154-162
Number of pages9
JournalMolecular Reproduction and Development
Volume54
Issue number2
Early online date1 Sep 1999
DOIs
Publication statusPublished - Oct 1999

Keywords

  • sex differentiation
  • fish
  • steroids
  • estrogens
  • aromatase
  • estrogen receptor
  • aromatase inhibitor
  • ovarian-differentiation
  • alligator embryos
  • EMYS-orbicularis
  • chicken embryos
  • enzyme-activity
  • receptor CDNA
  • teleost fish
  • gonads
  • temperature

Cite this

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title = "Involvement of estrogens in the process of sex differentiation in two fish species: The rainbow trout (Oncorhynchus mykiss) and a Tilapia (Oreochromis niloticus): The rainbow trout (Oncorhynchus mykiss) and a Tilapia (Oreochromis niloticus)",
abstract = "In order to study the physiological implication of sex steroid hormones in gonadal sex differentiation in fish, we first investigated the potential role of estrogens using two fish models: the rainbow trout (Oncorhynchus mykiss) and a tilapia species (Oreochromis niloticus). All experiments were carried out on genetically all-male (XY) and all-female (XX) populations. In vivo treatments with an aromatase inhibitor (ATD, 1,4,6- androstatriene3-17-dione) result in 100{\%} masculinization of an all-female population in rainbow trout (dosage 50 mg/kg of food) and 75.3{\%} in tilapia (dosage 150 mg/kg of food). In tilapia, the effectiveness of the aromatase inhibition by ATD is demonstrated by the marked decrease of the gonadal aromatase activity in treated animals versus control. No masculinization is obtained following treatment with an estrogen receptor antagonist (tamoxifen) in both species. Aromatase and estrogen receptor gene expression was studied in rainbow trout by semi-quantitative RT-PCR in gonads sampled before, during and after sex-differentiation. Aromatase mRNA is specifically detected in female gonads, 3 weeks before the first sign of histological sex-differentiation, i.e., first female meiosis. Aromatase expression in male gonads is at least a few hundred times less than in female gonads. Estrogen receptor gene is expressed in both male and female gonads at all stages with no dimorphic expression between sexes. Specific aromatase gene expression before ovarian differentiation was also demonstrated using virtual Northern blot, with no expression detected in male differentiating gonads. From these results it can be concluded that estrogen synthesis is crucial for ovarian differentiation, and transcription of the aromatase gene can be proposed as a key step in that process in fish. (C) 1999 Wiley-Liss, Inc.",
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author = "Y Guiguen and Baroiller, {J F} and Ricordel, {M J} and K Iseki and McMeel, {O M} and Martin, {Samuel Allen Moore} and A Fostier",
year = "1999",
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T1 - Involvement of estrogens in the process of sex differentiation in two fish species: The rainbow trout (Oncorhynchus mykiss) and a Tilapia (Oreochromis niloticus)

T2 - The rainbow trout (Oncorhynchus mykiss) and a Tilapia (Oreochromis niloticus)

AU - Guiguen, Y

AU - Baroiller, J F

AU - Ricordel, M J

AU - Iseki, K

AU - McMeel, O M

AU - Martin, Samuel Allen Moore

AU - Fostier, A

PY - 1999/10

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N2 - In order to study the physiological implication of sex steroid hormones in gonadal sex differentiation in fish, we first investigated the potential role of estrogens using two fish models: the rainbow trout (Oncorhynchus mykiss) and a tilapia species (Oreochromis niloticus). All experiments were carried out on genetically all-male (XY) and all-female (XX) populations. In vivo treatments with an aromatase inhibitor (ATD, 1,4,6- androstatriene3-17-dione) result in 100% masculinization of an all-female population in rainbow trout (dosage 50 mg/kg of food) and 75.3% in tilapia (dosage 150 mg/kg of food). In tilapia, the effectiveness of the aromatase inhibition by ATD is demonstrated by the marked decrease of the gonadal aromatase activity in treated animals versus control. No masculinization is obtained following treatment with an estrogen receptor antagonist (tamoxifen) in both species. Aromatase and estrogen receptor gene expression was studied in rainbow trout by semi-quantitative RT-PCR in gonads sampled before, during and after sex-differentiation. Aromatase mRNA is specifically detected in female gonads, 3 weeks before the first sign of histological sex-differentiation, i.e., first female meiosis. Aromatase expression in male gonads is at least a few hundred times less than in female gonads. Estrogen receptor gene is expressed in both male and female gonads at all stages with no dimorphic expression between sexes. Specific aromatase gene expression before ovarian differentiation was also demonstrated using virtual Northern blot, with no expression detected in male differentiating gonads. From these results it can be concluded that estrogen synthesis is crucial for ovarian differentiation, and transcription of the aromatase gene can be proposed as a key step in that process in fish. (C) 1999 Wiley-Liss, Inc.

AB - In order to study the physiological implication of sex steroid hormones in gonadal sex differentiation in fish, we first investigated the potential role of estrogens using two fish models: the rainbow trout (Oncorhynchus mykiss) and a tilapia species (Oreochromis niloticus). All experiments were carried out on genetically all-male (XY) and all-female (XX) populations. In vivo treatments with an aromatase inhibitor (ATD, 1,4,6- androstatriene3-17-dione) result in 100% masculinization of an all-female population in rainbow trout (dosage 50 mg/kg of food) and 75.3% in tilapia (dosage 150 mg/kg of food). In tilapia, the effectiveness of the aromatase inhibition by ATD is demonstrated by the marked decrease of the gonadal aromatase activity in treated animals versus control. No masculinization is obtained following treatment with an estrogen receptor antagonist (tamoxifen) in both species. Aromatase and estrogen receptor gene expression was studied in rainbow trout by semi-quantitative RT-PCR in gonads sampled before, during and after sex-differentiation. Aromatase mRNA is specifically detected in female gonads, 3 weeks before the first sign of histological sex-differentiation, i.e., first female meiosis. Aromatase expression in male gonads is at least a few hundred times less than in female gonads. Estrogen receptor gene is expressed in both male and female gonads at all stages with no dimorphic expression between sexes. Specific aromatase gene expression before ovarian differentiation was also demonstrated using virtual Northern blot, with no expression detected in male differentiating gonads. From these results it can be concluded that estrogen synthesis is crucial for ovarian differentiation, and transcription of the aromatase gene can be proposed as a key step in that process in fish. (C) 1999 Wiley-Liss, Inc.

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KW - fish

KW - steroids

KW - estrogens

KW - aromatase

KW - estrogen receptor

KW - aromatase inhibitor

KW - ovarian-differentiation

KW - alligator embryos

KW - EMYS-orbicularis

KW - chicken embryos

KW - enzyme-activity

KW - receptor CDNA

KW - teleost fish

KW - gonads

KW - temperature

U2 - 10.1002/(SICI)1098-2795(199910)54:2<154::AID-MRD7>3.0.CO;2-5

DO - 10.1002/(SICI)1098-2795(199910)54:2<154::AID-MRD7>3.0.CO;2-5

M3 - Article

VL - 54

SP - 154

EP - 162

JO - Molecular Reproduction and Development

JF - Molecular Reproduction and Development

SN - 1040-452X

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ER -