Identification and Modulation of a Growth Hormone-Binding Protein in Rainbow Trout (Oncorhynchus mykiss) Plasma during Seawater Adaptation

• Published in: General and comparative endocrinology Vol. 111; no. 2; pp. 216 - 224
• Main Authors: Sohm, Frédéric, Manfroid, Isabelle, Pezet, Alain, Rentier-Delrue, Françoise, Rand-Weaver, Mariann, Kelly, Paul A., Boeuf, Gilles, Postel-Vinay, Marie-Catherine, de Luze, Amaury, Edery, Marc
• Format: Journal Article Web Resource
• Language: English
• Published: United States Elsevier Inc 01-08-1998; Elsevier
• Subjects: Adaptation, Physiological; Anatomie (cytologie, histologie, embryologie...) & physiologie; Anatomy (cytology, histology, embryology...) & physiology; Animals; binding protein; Binding, Competitive; Brackish; Carrier Proteins - metabolism; Chromatography, High Pressure Liquid; Fish Proteins; Freshwater; Glycoproteins - metabolism; growth hormone; Growth Hormone - metabolism; Iodine Radioisotopes; Life sciences; Marine; Oncorhynchus mykiss; Oncorhynchus mykiss - blood; osmoregulation; Pituitary Hormones - metabolism; Precipitin Tests; receptor; Receptors, Somatotropin - metabolism; Recombinant Proteins; salmonid; Sciences du vivant; Seawater; somatolactin; somatolactin; osmoregulation; salmonid; receptor; growth hormone; binding protein
• ISSN: 0016-6480; 1095-6840; 1095-6840
• DOI: 10.1006/gcen.1998.7106

A soluble protein that specifically bound125I-human growth hormone (hGH) was identified in rainbow trout plasma, using HPLC-gel filtration. The binding affinity of the protein for hGH was 1.2 × 109M−1.125I-rainbow trout GH (tGH) was also able to bind to the protein albeit with a lower affinity (6.6×107M−1) than hGH. Crosslinking experiments using125I-hGH revealed two specific bands of 150 and 130 kDa. The complex125I-hGH–BP could be precipitated by a monoclonal anti-GH receptor antibody, suggesting a close relationship between the plasma GH-BP and the GH receptor. A fourfold increase in the hGH binding to the GH-BP was shown 48 h after transfer of the fishes from freshwater to seawater. The increase in binding was related to a high binding capacity without significant changes in binding affinity. These results suggest a potential role of this related GH-BP as an index of GH effects during seawater adaptation in salmonids.