Expression of insulin-like growth factor I gene in osmoregulatory organs during seawater adaptation of the salmonid fish: Possible mode of osmoregulatory action of growth hormone

Tatsuya Sakamoto, Tetsuya Hirano

Research output: Contribution to journalArticlepeer-review

156 Citations (Scopus)

Abstract

Growth hormone has been shown to contribute to seawater adaptation of salmonid fishes. The growth influence of growth hormone is mediated largely by hepatic production of insulin-like growth factor I (IGF-I). To study the growth hormone-IGF-I axis in osmoregulation, we measured IGF-I mRNA in the liver, gill, and body kidney from rainbow trout by Northern analysis. The levels of IGF-I mRNA in all tissues increased significantly after injection of growth hormone. Transfer of trout from fresh water to 80% seawater evoked an increase in plasma growth hormone after 1 day. IGF-I mRNA was not altered significantly in the liver, but it was increased in the gill and body kidney after 1 and 8 days, respectively. These observations indicate that the IGF-I gene is expressed differently among these organs during seawater adaptation. Growth hormone may stimulate hypoosmoregulatory ability by inducing local expression of IGF-I in osmoregulatory organs, although the possibility that IGF-I expression might occur in part independently of growth hormone during seawater adaptation cannot be excluded.

Original languageEnglish
Pages (from-to)1912-1916
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number5
DOIs
Publication statusPublished - Mar 1 1993
Externally publishedYes

Keywords

  • Gene regulation
  • Gill
  • Kidney
  • RNA hybridization
  • Rainbow trout

ASJC Scopus subject areas

  • General

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