Characterization of an insulin-like growth factor (IGF) receptor and the insulin-like effects of IGF-1 in the bony fish, Lates calcarifer.

The present work is part of a broad phylogenetic study of the insulin superfamily of peptides in lower vertebrates. In the bony fish barramundi (Lates calcarifer), the presence of IGF receptors were investigated in the liver by means of competitive binding studies. The results suggested the presence of a type 1-like but no type 2-like IGF receptor. We also demonstrated insulin-like effects of intraperitoneally injected recombinant human (rh)-IGF-1 in barramundi with rh-IGF-1 and rh-insulin showing similar effects with respect to induction of hypoglycemia and stimulation of incorporation of [14C]-glucose into muscle glycogen.