Identification of insulin-like growth factor-binding proteins in the circulation of four teleost fish species

✍ Scribed by Kelley, Kevin M. ;Siharath, Kimmakone ;Bern, Howard A.

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 589 KB
• Volume: 263
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402630213

✦ Synopsis

Abstract

Insulin‐like growth factor‐binding proteins (IGF‐BPs) were demonstrated in the circulation of four teleost fish species. In the coho salmon (Oncorhynchus kisutch), serum binding of ^125^I‐labelled human IGF‐I (^125^I‐hIGF‐I) was competitively inhibited by addition of excess recombinant bovine IGF‐I (rbIGF‐I) in a manner similar to that when rat serum was used. Western‐ligand blot procedure using the same labelled hormone identified at least three major forms of IGF‐BPs in the plasma of all four teleost species investigated: coho salmon, striped bass (Morone saxatilis), tilapia (Oreochromis mossambicus), and longjawed mudsucker (Gillichthys mirabilis). The first form is around 40–50 kDa, may be regulated by growth hormone (GH), and seems to be a good candidate for the fish version of mammalian IGF‐BP3 (which is in the same size range and is GH‐regulated). The second and third forms are 29 kDa and 31 kDa and are good candidates for the fish versions of mammalian IGF‐BP1 and IGF‐BP2, respectively, as they appear to be regulated by insulin and are in the same size range as their mammalian counterparts. Functionally different classes of circulating IGF‐BPs may be conserved between fish and mammal. © 1992 Wiley‐Liss, Inc.