Changes in brain seabream GnRH mRNA and pituitary seabream GnRH peptide levels during ovarian maturation in female barfin flounder.
The pleuronectid barfin flounder Verasper moseri expresses three forms of gonadotropin-releasing hormones (GnRHs), i.e., seabream GnRH (sbGnRH), salmon GnRH, and chicken GnRH-II. Among these, sbGnRH is the dominant form in the pituitary, indicating that sbGnRH regulates gonadal maturation. In order to clarify the physiological roles of sbGnRH during ovarian maturation in reared female barfin flounder, the changes in brain sbGnRH mRNA levels and pituitary sbGnRH peptide levels were examined by real-time quantitative PCR and time-resolved fluoroimmunoassay, respectively. The fish hatched in April 2002. The gonadosomatic index remained low until August 2004 and increased thereafter until April 2005 when the fish began to ovulate. The sbGnRH mRNA levels per brain increased significantly from April 2004 to April 2005. Pituitary sbGnRH peptide levels also increased significantly during this period. These results indicate that sbGnRH is involved in ovarian maturation and ovulation in the barfin flounder.
Amano
Masafumi
M
School of Marine Biosciences, Kitasato University, Sanriku, Ofunato, Iwate 022-0101, Japan. amanoma@kitasato-u.ac.jp
Pham
Ky Xuan
KX
Amiya
Noriko
N
Yamanome
Takeshi
T
Yamamori
Kunio
K
D000818:Animals; D001921:Brain / Q000378:metabolism / Q000502:physiology*; D004958:Estradiol / Q000097:blood; D005260:Female; D005432:Flounder / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015200:Fluoroimmunoassay; D007987:Gonadotropin-Releasing Hormone / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D006651:Histocytochemistry / Q000662:veterinary; D006908:Hydroxyprogesterones / Q000097:blood; D010053:Ovary / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D010902:Pituitary Gland / Q000378:metabolism / Q000502:physiology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D012741:Sexual Maturation / Q000502:physiology*; D013739:Testosterone / Q000097:blood
D006908:Hydroxyprogesterones; D020033:Protein Isoforms; D012333:RNA, Messenger; C007433:17,20-dihydroxy-4-pregnen-3-one; D007987:Gonadotropin-Releasing Hormone; D013739:Testosterone; D004958:Estradiol