Papers

Peer-reviewed
Jun, 2000

Effects of gonadotropin-releasing hormone analog on expression of genes encoding the growth hormone/prolactin/somatolactin family and a pituitary-specific transcription factor in the pituitaries of prespawning sockeye salmon

GENERAL AND COMPARATIVE ENDOCRINOLOGY
  • S Taniyama
  • ,
  • T Kitahashi
  • ,
  • H Ando
  • ,
  • M Kaeriyama
  • ,
  • Y Zohar
  • ,
  • H Ueda
  • ,
  • A Urano

Volume
118
Number
3
First page
418
Last page
424
Language
English
Publishing type
Research paper (scientific journal)
DOI
10.1006/gcen.2000.7480
Publisher
ACADEMIC PRESS INC

Gonadotropin-releasing hormone (GnRH) is a possible secretagogue of growth hormone (GH) and somatolactin (SL) in teleosts. Effects of GnRH on the levels of pituitary mRNAs encoding GH, prolactin (PRL), and SL were therefore examined in prespawning sockeye salmon (Oncorhynchus nerka). A capsule of GnRH analog (GnRHa) was implanted into the dorsal muscle of maturing sockeye salmon for 3 weeks. The levels of hormonal mRNAs were then determined by a quantitative dot blot analysis using single-stranded sense DNA of the same sequence of mRNA as the standard. Further, we analyzed effects of GnRHa on expression of the genes encoding pituitary-specific transcription factor (Pit-1/GHF-1). Relative levels of Pit-1/GHF-1 mRNAs were estimated by Northern blot analysis, which showed specific 2- and 3-kb bands of mRNAs. GnRHa significantly increased the level of SL mRNA in the males, but not in the females, compared to the control fish. It did not induce significant increases in the levels of GH and PRL mRNAs in both the males and the females. The levels of Pit-1/GHF-1 mRNAs in the control males tended to be higher than those in the initial controls, so that GnRHa might not be effective in enhancing expression of Pit-1/GHF-1 gene, except for the level of 3-kb Pit-1/GHF-1 mRNA in the females treated with 150 lug GnRHa. The pattern of changes in the levels of Pit-1/ GHF-1 mRNAs were similar to those of GH and PRL mRNAs in both the males and the females and to that of SL mRNA in the females. These results indicate that, in prespawning sockeye salmon, GnRH can stimulate SL gene expression, but probably not through the Pit-1/ GHF-1-dependent system. (C) 2000 Academic Press.

Link information
DOI
https://doi.org/10.1006/gcen.2000.7480
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/10843793
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000087760400007&DestApp=WOS_CPL
ID information
  • DOI : 10.1006/gcen.2000.7480
  • ISSN : 0016-6480
  • Pubmed ID : 10843793
  • Web of Science ID : WOS:000087760400007

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