Generation of Chicken Growth Hormone-Binding Proteins by Proteolysis

Vleurick, Lieve; Kuhn, Er; Decuypere, Eddy; Burnside, Joan; Pezet, Alain; Edery, Marc

doi:10.1006/gcen.1998.7202

Cited by 16 publications

(6 citation statements)

References 30 publications

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“…It is therefore possible that GH has autocrine and paracrine roles in early embryonic growth (Harvey et al 1998), especially as GH-receptor (GHR) immunoreactivity is also present in most tissues of embryonic chicks (Harvey et al 1998(Harvey et al , 2000(Harvey et al , 2001a. GHR immunoreactivity could, however, reflect the presence of GH-binding proteins (GHBPs), rather than authentic receptors linked to intracellular signal transduction mechanisms (Monsonego et al 1997;Vleurick et al 1999). GHR-immunoreactivity may not, therefore, be indicative of GH target tissues.…”

Section: Introductionmentioning

confidence: 98%

Growth hormone (GH) action in early embryogenesis: expression of a GH-response gene in sites of GH production and action

Harvey¹,

Lavelin

Pines

2001

Anatomy and Embryology

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Growth hormone (GH) may act as a local growth factor in early embryonic development, since GH- and GH-receptor (GHR) immunoreactivity is present in all tissues and most cells of embryonic chicks during organogenesis. However, as GHR-immunoreactivity could, alternatively, reflect the presence of GH-binding proteins (GHBPs) rather than authentic receptors linked to signal transduction mechanisms, GHR immunoreactivity may not be indicative of GH target sites. The possibility that GH may act as an autocrine or paracrine factor during embryogenesis was therefore assessed in the present study by determining the presence and cellular localization of mRNA for a GH-responsive gene. The mechanism of GH action involves the induction of a number of specific GH-response genes. In chickens a novel GH-responsive gene (GHRG-1) has been identified as a marker of GH action. In situ hybridization, using a 860 bp probe for GHRG-1 mRNA, demonstrated widespread expression of the GHRG-1 gene in embryonic tissues known to contain GH- and GHR-immunoreactivity (e.g. in the spinal cord, skin, heart, liver, muscle, bone and lung). GHRG-1 mRNA was not, however, present in all cells of each tissue. It was, furthermore, not present in subepithelial cells of the esophagus and bronchus and was lacking in many spinal cord ependyma, which are also known to lack GH immunoreactivity. These results therefore support the possibility that GH acts as an autocrine/paracrine factor during early chick embryogenesis, which was hitherto thought to be a "growth-without-GH" syndrome.

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Section: Introductionmentioning

confidence: 98%

Growth hormone (GH) action in early embryogenesis: expression of a GH-response gene in sites of GH production and action

Harvey¹,

Lavelin

Pines

2001

Anatomy and Embryology

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“…Heightened expression of GHR mRNA in liver and muscle throughout late embryonic development may be used for GH binding protein (GHBP) synthesis, which is made by cleaving off GHR's extracellular domain (Vleurick et al, 1999;Lau et al, 2007). Human GHBPs form a complex with GH FIGURE 6 | Relative mRNA expression of (A) IGFBP1, (B) IGFBP2, (C) IGFBP3, (D) IGFBP4, (E) IGFBP5, and (F) IGFBP7 in liver on embryonic e days 10, 12, 14, 16, and 18 in legacy ACRB and modern Ross 308 male broilers.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Commercial Genetic Selection on Somatotropic Gene Expression in Broilers: A Potential Role for Insulin-Like Growth Factor Binding Proteins in Regulating Broiler Growth and Body Composition

2022

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The somatotropic axis influences growth and metabolism, and many of its effects are a result of insulin-like growth factor (IGF) signaling modulated by IGF-binding proteins (IGFBPs). Modern commercial meat-type (broiler) chickens exhibit rapid and efficient growth and muscle accretion resulting from decades of commercial genetic selection, and it is not known how alterations in the IGF system has contributed to these improvements. To determine the effect of commercial genetic selection on somatotropic axis activity, two experiments were conducted comparing legacy Athens Canadian Random Bred and modern Ross 308 male broiler lines, one between embryonic days 10 and 18 and the second between post-hatch days 10 and 40. Gene expression was evaluated in liver and breast muscle (pectoralis major) and circulating hormone concentrations were measured post-hatch. During embryogenesis, no differences in IGF expression were found that corresponded with difference in body weight between the lines beginning on embryonic day 14. While hepatic IGF expression and circulating IGF did not differ between the lines post-hatch, expression of both IGF1 and IGF2 mRNA was greater in breast muscle of modern broilers. Differential expression of select IGFBPs suggests their action is dependent on developmental stage and site of production. Hepatic IGFBP1 appears to promote embryonic growth but inhibit post-hatch growth at select ages. Results suggest that local IGFBP4 may prevent breast muscle growth during embryogenesis but promote it after hatch. Post-hatch, IGFBP2 produced in liver appears to inhibit body growth, but IGFBP2 produced locally in breast muscle facilitates development of this tissue. The opposite appears true for IGFBP3, which seems to promote overall body growth when produced in liver and restrict breast muscle growth when produced locally. Results presented here suggest that paracrine IGF signaling in breast muscle may contribute to overall growth and muscle accretion in chickens, and that this activity is regulated in developmentally distinct and tissue-specific contexts through combinatorial action of IGFBPs.

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“…In fish as in most mammals, GHBPs are principally generated through proteolysis of the full-length GHR ( 32 , 53 , 54 ), rather than through alternative splicing of the ghr gene, as in rodents ( 55 , 56 ). However, truncated ghr genes encoding for the extracellular GHR domain have been identified in both early and late vertebrates such as sea lamprey ( 57 ) and human ( 53 ) as well as zebrafish ( 58 ), representing an alternative production pathway for plasma GHBPs.…”

Section: Discussionmentioning

confidence: 99%

The Impact of Initial Energy Reserves on Growth Hormone Resistance and Plasma Growth Hormone-Binding Protein Levels in Rainbow Trout Under Feeding and Fasting Conditions

et al. 2018

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The growth hormone (GH)–insulin-like growth factor I (IGF-I) system regulates important physiological functions in salmonid fish, including hydromineral balance, growth, and metabolism. While major research efforts have been directed toward this complex endocrine system, understanding of some key aspects is lacking. The aim was to provide new insights into GH resistance and growth hormone-binding proteins (GHBPs). Fish frequently respond to catabolic conditions with elevated GH and depressed IGF-I plasma levels, a condition of acquired GH resistance. The underlying mechanisms or the functional significance of GH resistance are, however, not well understood. Although data suggest that a significant proportion of plasma GH is bound to specific GHBPs, the regulation of plasma GHBP levels as well as their role in modulating the GH–IGF-I system in fish is virtually unknown. Two in vivo studies were conducted on rainbow trout. In experiment I, fish were fasted for 4 weeks and then refed and sampled over 72 h. In experiment II, two lines of fish with different muscle adiposity were sampled after 1, 2, and 4 weeks of fasting. In both studies, plasma GH, IGF-I, and GHBP levels were assessed as well as the hepatic gene expression of the growth hormone receptor 2a (ghr2a) isoform. While most rainbow trout acquired GH resistance within 4 weeks of fasting, fish selected for high muscle adiposity did not. This suggests that GH resistance does not set in while fat reserves as still available for energy metabolism, and that GH resistance is permissive for protein catabolism. Plasma GHBP levels varied between 5 and 25 ng ml−1, with large fluctuations during both long-term (4 weeks) fasting and short-term (72 h) refeeding, indicating differentiated responses depending on prior energy status of the fish. The two opposing functions of GHBPs of prolonging the biological half-life of GH while decreasing GH availability to target tissues makes the data interpretation difficult, but nutritional regulatory mechanisms are suggested. The lack of correlation between hepatic ghr2a expression and plasma GHBP levels indicate that ghr2a assessment cannot be used as a proxy measure for GHBP levels, even if circulating GHBPs are derived from the GH receptor molecule.

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Generation of Chicken Growth Hormone-Binding Proteins by Proteolysis

Cited by 16 publications

References 30 publications

Growth hormone (GH) action in early embryogenesis: expression of a GH-response gene in sites of GH production and action

Growth hormone (GH) action in early embryogenesis: expression of a GH-response gene in sites of GH production and action

The Effect of Commercial Genetic Selection on Somatotropic Gene Expression in Broilers: A Potential Role for Insulin-Like Growth Factor Binding Proteins in Regulating Broiler Growth and Body Composition

The Impact of Initial Energy Reserves on Growth Hormone Resistance and Plasma Growth Hormone-Binding Protein Levels in Rainbow Trout Under Feeding and Fasting Conditions

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