Characterization of a novel growth hormone receptor-encoding cDNA in rainbow trout and regulation of its expression by nutritional state.

To clarify the divergence of the growth hormone receptor (GHR) family, we characterized a novel GHR from a teleost fish (rainbow trout). A 2357-nt cDNA was isolated and found to contain a single initiation site 71 nt from the most 5' end, an open reading frame of 1971 nt encoding a 657-amino acid protein, and a single polyadenylation site 229 nt from the poly-A tail. Based on structural analysis, the protein was identified as a type 1 GHR (GHR1).

Differential expression of preprosomatostatin- and somatostatin receptor-encoding mRNAs in association with the growth hormone-insulin-like growth factor system during embryonic development of rainbow trout (Oncorhynchus mykiss).

Rainbow trout were used to evaluate the relationship between the somatostatin (SS) signaling and the growth hormone (GH)-insulin-like growth factor (IGF) systems during pre-hatch and post-hatch embryonic development. The expression of preprosomatostatins (PPSS), SS receptors (SSTR), GH receptors (GHR), IGF-1, IGF-2, and IGF type 1 receptors (IGFR1) was examined in various regions at the eyed-egg (29 days post-fertilization, dpf;), post-hatch (53dpf), swim-up (68dpf), and complete yolk-absorbed (90dpf) stages. In head, PPSSI mRNA abundance increased during development while that of PPSSII' decreased and that of PPSSII'' remained unchanged.