Steroid hormones (17β-estradiol and hydrocortisone) upregulate hepatocyte nuclear factor (HNF)-3β and insulin-like growth factors I and II expression in the gonads of tilapia (Oreochromis mossambicus) in vitro

Hepatocyte nuclear factors (HNF-1α, -1β and -3β) and insulin-like growth factors (IGF-I and -II), which are involved in liver-specific gene expression, metabolism, development and cell growth, have been found in the gonads of tilapia (Oreochromis mossambicus). However, the functions of these factors...

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Bibliographic Details
Published in:Theriogenology 2006, Vol.68, p.988-1002
Main Authors: Huang, W.T, Yu, H.C, Hsu, C.C, Liao, C.F, Gong, H.Y, Lin, C.J.F, Wu, J.L, Weng, C.F
Format: Article
Language:English
Subjects:
cortisol
dose response
estradiol
fish
gene expression regulation
gene induction
gene upregulation
gonads
hormonal regulation
immunohistochemistry
immunolocalization
insulin-like growth factor I
insulin-like growth factor II
messenger RNA
Oreochromis mossambicus
steroid hormones
transcription factors
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Summary:Hepatocyte nuclear factors (HNF-1α, -1β and -3β) and insulin-like growth factors (IGF-I and -II), which are involved in liver-specific gene expression, metabolism, development and cell growth, have been found in the gonads of tilapia (Oreochromis mossambicus). However, the functions of these factors and how they interact within the gonads of bony fish are not understood. In the present study, we provided experimental evidence that the expression of HNF-3β in the gonads of tilapia, but not HNF-1α and -1β, was affected in vitro by 17β-estradiol and hydrocortisone. Immunohistochemical staining confirmed that tilapia HNF-3β was mainly found in the nuclei of hepatocytes, the follicular granulosa cells of the ovaries, and the interstitial cells of the testes of adult tilapia. Further data were gathered at various steroid concentrations (0.1, 1, 10, 100, and 1000 nM) over various culture intervals (6, 12, 18, 24, 30, and 36 h) and subjected to semi-quantitative RT-PCR analysis. The expression of downstream genes (IGF-I and -II) followed the same temporal patterns as HNF-3β, albeit at decreased levels for 30 and 36 h culture intervals. Both hormones upregulated HNF-3β mRNA expression at concentrations of 0.1-10 nM, and reached optimal physiological concentrations for induction of IGFs at 1-10 nM. The identity of the PCR fragments was concurrently verified by sequencing and PCR-Southern hybridization. We inferred that HNF-3β and IGFs may play a regulatory role in tilapia gonads during oocyte maturation and spermatogenesis.
ISSN:0093-691X
1879-3231