Plasma growth hormone-binding protein levels in Atlantic salmon Salmo salar during smoltification and seawater transfer.

Specific growth hormone (GH)-binding protein (Ghbp) was purified from Atlantic salmon Salmo salar and rainbow trout Oncorhynchus mykiss plasma with immunoprecipitation and characterized in cross-linking studies using autoradiography and western blots. The size of the Ghbp was estimated to be c. 53 kDa. A radioimmunoassay was established to measure Ghbp in salmonids, using antibodies specific against the extracellular segment of the S. salar growth hormone receptor 1 (grh1; GenBank AY462105). Plasma Ghbp levels were measured in S. salar smolts in fresh water and after transfer to seawater (SW; experiments 1 and 2), and in post-smolts kept at different salinities (0, 12, 22 and 34) for 3 months (experiment 3). A transient increase in plasma Ghbp, which lasted for 1 month or less, was noted in smolts after transfer to SW. Concomitantly, plasma GH and gill Na(+) -K(+) -ATPase activity increased during smoltification (in experiment 2). No difference in plasma Ghbp was evident between post-smolts kept at different salinities, although the fish kept at salinity 34 had higher plasma GH than the group kept at salinity 22 and higher hepatic ghr1 expression than post-smolts kept at salinity 12. This suggests that plasma Ghbp regulation may respond to salinity changes in the short term. The lack of correlation between Ghbp, plasma GH and hepatic ghr1 expression in the long-term post-smolt experiment indicates that Ghbp levels may be regulated independently of other components of the endocrine GH system in salmonids.

[1]  S. McCormick,et al.  Prolactin and growth hormone in fish osmoregulation. , 2006, General and comparative endocrinology.

[2]  G. Baumann,et al.  Growth hormone binding protein. The soluble growth hormone receptor. , 2002, Minerva endocrinologica.

[3]  David C. Lee,et al.  An essential role for ectodomain shedding in mammalian development. , 1998, Science.

[4]  B. Björnsson,et al.  The interrelation between photoperiod, growth hormone, and sexual maturation of adult Atlantic salmon (Salmo salar). , 1994, General and comparative endocrinology.

[5]  S. McCormick,et al.  Development of intestinal ion-transporting mechanisms during smoltification and seawater acclimation in Atlantic salmon Salmo salar. , 2014, Journal of fish biology.

[6]  P. Kelly,et al.  Identification and modulation of a growth hormone-binding protein in rainbow trout (Oncorhynchus mykiss) plasma during seawater adaptation. , 1998, General and comparative endocrinology.

[7]  B. Björnsson The biology of salmon growth hormone: from daylight to dominance , 1997, Fish Physiology and Biochemistry.

[8]  B. Björnsson,et al.  Regulation of skeletal muscle growth in fish by the growth hormone--insulin-like growth factor system. , 2013, General and comparative endocrinology.

[9]  Katie M. Reindl,et al.  Peripheral regulation of the growth hormone-insulin-like growth factor system in fish and other vertebrates. , 2012, Comparative biochemistry and physiology. Part A, Molecular & integrative physiology.

[10]  Nicole Nelson,et al.  A metalloproteinase disintegrin that releases tumour-necrosis factor-α from cells , 1997, Nature.

[11]  T. Ágústsson,et al.  Osmoregulation, feed intake, growth and growth hormone levels in 0+ Atlantic salmon (Salmo salar L.) transferred to seawater at different stages of smolt development , 2003 .

[12]  A. Meyer,et al.  Evolution of Receptors for Growth Hormone and Somatolactin in Fish and Land Vertebrates: Lessons from the Lungfish and Sturgeon Orthologues , 2007, Journal of Molecular Evolution.

[13]  T. Ágústsson,et al.  Growth Hormone Endocrinology of Salmonids: Regulatory Mechanisms and Mode of Action , 2002, Fish Physiology and Biochemistry.

[14]  Z. Liao,et al.  Identification and characterization of GH receptor and serum GH-binding protein in Chinese sturgeon (Acipenser sinensis). , 2004, Acta biochimica et biophysica Sinica.

[15]  B. Björnsson,et al.  Cloning of two Atlantic salmon growth hormone receptor isoforms and in vitro ligand-binding response , 2005, Fish Physiology and Biochemistry.

[16]  P. Kiilerich,et al.  Hormone receptors in gills of smolting Atlantic salmon, Salmo salar: expression of growth hormone, prolactin, mineralocorticoid and glucocorticoid receptors and 11beta-hydroxysteroid dehydrogenase type 2. , 2007, General and comparative endocrinology.

[17]  J. Kopchick,et al.  Growth hormone (GH), GH receptor, and signal transduction. , 2000, Molecular genetics and metabolism.

[18]  T. Marchant,et al.  Identification of serum GH-binding proteins in the goldfish (Carassius auratus) and comparison with mammalian GH-binding proteins. , 1999, The Journal of endocrinology.

[19]  B. Björnsson,et al.  Growth hormone endocrinology of Atlantic salmon (Salmo salar): pituitary gene expression, hormone storage, secretion and plasma levels during parr-smolt transformation. , 2001, The Journal of endocrinology.

[20]  S. McCormick,et al.  Methods for Nonlethal Gill Biopsy and Measurement of Na+, K+-ATPase Activity , 1993 .

[21]  T. Marchant,et al.  Characterization of growth hormone binding sites in the goldfish,Carassius auratus: effects of hypophysectomy and hormone injection , 1996, Fish Physiology and Biochemistry.

[22]  T. Storebakken,et al.  Growth rate estimates for cultured Atlantic salmon and rainbow trout , 1987 .

[23]  R. Black,et al.  Tumor Necrosis Factor-α Converting Enzyme (TACE) Is a Growth Hormone Binding Protein (GHBP) Sheddase: The Metalloprotease TACE/ADAM-17 Is Critical for (PMA-Induced) GH Receptor Proteolysis and GHBP Generation. , 2000, Endocrinology.

[24]  Darren T. Lerner,et al.  Taking it with you when you go: How perturbations to the freshwater environment, including temperature, dams, and contaminants, affect marine survival of salmon. , 2009 .

[25]  S. McCormick Endocrine Control of Osmoregulation in Teleost Fish1 , 2001 .

[26]  B. Björnsson,et al.  Molecular mechanisms of continuous light inhibition of Atlantic salmon parr-smolt transformation , 2007 .

[27]  S. McCormick,et al.  Osmoregulatory actions of growth hormone and its mode of action in salmonids: A review , 1993, Fish Physiology and Biochemistry.

[28]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[29]  G. Baumann Growth Hormone Binding Protein 2001 , 2001, Journal of pediatric endocrinology & metabolism : JPEM.

[30]  M. Reinecke Influences of the environment on the endocrine and paracrine fish growth hormone-insulin-like growth factor-I system. , 2010, Journal of fish biology.

[31]  B. Björnsson,et al.  Growth, osmoregulation and endocrine changes in wild Atlantic salmon smolts and post-smolts during marine migration , 2012 .

[32]  P. Kiilerich,et al.  Endocrine systems in juvenile anadromous and landlocked Atlantic salmon (Salmo salar): seasonal development and seawater acclimation. , 2008, General and comparative endocrinology.

[33]  S. Takeda,et al.  [Growth hormone-binding protein]. , 1999, Nihon rinsho. Japanese journal of clinical medicine.

[34]  T. Nilsen,et al.  Exposure to continuous light disrupts retinal innervation of the preoptic nucleus during parr-smolt transformation in Atlantic salmon , 2007 .

[35]  S. McCormick HORMONAL CONTROL OF METABOLISM AND IONIC REGULATION | The Hormonal Control of Osmoregulation in Teleost Fish , 2011 .

[36]  M. Lambert,et al.  Cloning of a disintegrin metalloproteinase that processes precursor tumour-necrosis factor-α , 1997, Nature.

[37]  B. Björnsson,et al.  Seawater adaptation by out-of-season Atlantic salmon (Salmo salar L.) smolts at different temperatures , 2000 .

[38]  Zhiyong Liao,et al.  Molecular cloning and functional analysis of Chinese sturgeon (Acipenser sinensis) growth hormone receptor , 2009, Science in China Series C: Life Sciences.