title: Expression of growth hormone family and growth hormone receptor during early development in the Japanese eel (Anguilla japonica).
abstract: In a previous study, we identified cDNAs encoding the growth hormone receptor (eGHR1) and eGHR1 homologue (eGHR2) in Japanese eel (Anguilla japonica). In the present study, changes in the developmental expression of growth hormone (GH), eGHR1 and eGHR2 were investigated in the Japanese eel eggs and preleptocephali by RT-PCR and immunohistochemical methods in an attempt to examine the involvement of these proteins in larval growth. The GH transcripts and the production of GH protein were not detected in the newly hatched larvae and preleptocephali at day 3 post-hatch, however, these were detected at day 6 post-hatch, and also detected at higher levels at day 10 post-hatch. In contrast, prolactin and somatolactin transcripts could not be detected in all preleptocephalus specimens (newly hatched larvae and preleptocephali at day 3, 6 and 10 post-hatch). eGHR1 and eGHR2 transcripts were detected in all preleptocephalus specimens. Therefore, it is plausible that the actions of GH during the preleptocephalus stage are mediated through the eGHRs. The present data suggest that GHR-mediated actions of GH begin at the same time as the initiation of GH production, and that GH plays important roles in larval growth and survival to the leptocephalus stage. eGHR1 mRNA, which is thought to be of maternal origin, was also detected in ovulated eggs. However, the role of eGHR1 mRNA in eggs is not clear.
authors.affiliation: Division of Marine Biosciences, Graduate School of Fisheries Sciences, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan. yozaki@lab.nig.ac.jp <yozaki@lab.nig.ac.jp>
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Ozaki
authors.forename: Haruhisa
authors.initials: H
authors.lastname: Fukada
authors.forename: Hideki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Kagawa
authors.forename: Hiromi
authors.initials: H
authors.lastname: Ohta
authors.forename: Shinji
authors.initials: S
authors.lastname: Adachi
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hara
authors.forename: Kohei
authors.initials: K
authors.lastname: Yamauchi
mesh_terms: D000811:Anguilla / Q000254:growth & development* / Q000378:metabolism*; D000818:Animals; D005260:Female; D005786:Gene Expression Regulation; D013006:Growth Hormone / Q000378:metabolism*; D007150:Immunohistochemistry; D011986:Receptors, Somatotropin / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D011986:Receptors, Somatotropin; D011994:Recombinant Proteins; D013006:Growth Hormone