Molecular characterization of LH-beta and FSH-beta subunits and their regulation by estrogen in the goldfish pituitary.
The gonadal steroids, along with gonadotropin-releasing hormone (GnRH) are involved in the regulation of gonadotropin (GtH) production in vertebrates. Goldfish have an annual reproductive cycle, characterized by seasonal fluctuations in the circulating levels of the reproductive hormones, including 17beta-estradiol (E2). The purpose of the present study was to investigate the effect of E2 on basal and GnRH-induced GtH subunit (alpha, FSH-beta and LH-beta) gene expression in the goldfish pituitary. Northern analyses were performed to determine changes in steady state mRNA levels. Both in vivo and in vitro treatment with E2 resulted in a stimulation of all three GtH subunit mRNA levels, although a higher concentration was required for the stimulation of the FSH-beta subunit mRNA levels. The effect of E2 on GnRH-induced GtH mRNA level was also investigated and demonstrated that E2 influences the GnRH-induced GtH subunit mRNA levels in a seasonally dependent manner. Overall, the present results indicate that E2 stimulates GtH subunit mRNA levels directly at the level of the pituitary in a seasonally dependent manner in goldfish.
Huggard-Nelson
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DL
Department of Biological Sciences, University of Calgary, 2500 University Drive N.W., Calgary, Alta., Canada T2N 1N4.
Nathwani
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Kermouni
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Habibi
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D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology; D005640:Follicle Stimulating Hormone / Q000235:genetics* / Q000378:metabolism; D037201:Follicle Stimulating Hormone, beta Subunit; D005786:Gene Expression Regulation / Q000187:drug effects*; D006054:Goldfish / Q000235:genetics*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006062:Gonadotropins / Q000235:genetics* / Q000378:metabolism; D007986:Luteinizing Hormone / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D037201:Follicle Stimulating Hormone, beta Subunit; D006062:Gonadotropins; D012333:RNA, Messenger; D012337:RNA, Ribosomal, 18S; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone