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Real-time PCR analysis of ovary- and brain-type aromatase gene expression during Atlantic halibut (Hippoglossus hippoglossus) development

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1016/j.cbpb.2006.02.008
AuthorSearch for: 1; Search for: ; Search for: ; Search for: ; Search for: 2
Affiliation
  1. National Research Council of Canada. NRC Institute for Marine Biosciences
  2. National Research Council of Canada. Aquatic and Crop Resource Development
FormatText, Article
Subjectsexual differentiation; gonadal differentiation; Atlantic halibut; aromatase; cyp19a; cyp19b
Abstract
Two forms of cytochrome P450 aromatase, acting in both the brain and the ovary, have been implicated in controlling ovarian development in fish. To better understand the expression of these two enzymes during sexual differentiation in Atlantic halibut (Hippoglossus hippoglossus), real-time PCR was used to quantify the mRNA levels of ovary- (cyp19a) and brain-type cytochrome P450 aromatase (cyp19b) genes in the gonad and brain during gonadal development. Both enzymes showed high levels of expression in both tissues in developmental stages prior to histologically detectable ovarian differentiation (38 mm fork length), with increased expression occurring slightly earlier in the brain than the gonad. Cyp19a showed a second peak of expression in later stages (> 48 mm) in the gonad, but not the brain. Cyp19b expression was generally higher in the brain than the gonad. These results suggest that sexual differentiation may begin in the brain prior to gonadal differentiation, supporting the idea that steroid hormone expression in the brain is a key determinant of phenotypic sex in fish. In an examination of sexually immature adults, cyp19a was highly expressed in female gonad while cyp19b was very highly expressed in the pituitary of both sexes. The ratio of cyp19a to cyp19b expression was much higher in ovaries than in testes in the adult fish, so this ratio was analyzed in the developing gonads of juvenile halibut in an attempt to infer their sex. This was only partially successful, with about half the fish in later developmental stages showing apparently sex-specific differences in aromatase expression.
Publication date
In
  • Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 144, no. 1 (May 2006): 128–135.
LanguageEnglish
Peer reviewedYes
NRC numberNRCC 55545
1566
NPARC number3538474
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Record identifier25140273-e9e0-49d8-9823-ac4dfdaf2cca
Record created2009-03-01
Record modified2020-04-22
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