Expression of insulin-like growth factor I gene in osmoregulatory organs during seawater adaptation of the salmonid fish: possible mode of osmoregulatory action of growth hormone.

Sakamoto, Tatsuya; Hirano, Tetsuya

doi:10.1073/pnas.90.5.1912

Cited by 159 publications

(77 citation statements)

References 51 publications

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“…igf1 expression, which, as expected, was much higher in the liver than the gill, responded to SW with a tenfold increase in the gill and a tenfold decrease in the liver. The increase in the gill confirmed the reports in rainbow trout by Sakamoto & Hirano (1993) and Poppinga et al (2007), and suggests paracrine actions of Igf1 to be involved in modification of ion transport in the gill. The decrease in the liver was surprising and is at variance with Poppinga et al (2007), but may be explained by our additional observation that cortisol has a strong inhibitory effect on hepatic igf1 expression.…”

Section: Endocrine and Paracrine Mechanisms Of Actionsupporting

confidence: 76%

“…Gh injection elevated both liver and gill igf1 mRNA, and thus parallels findings in injection experiments in rainbow trout (Sakamoto & Hirano 1993) and in vitro data from coho salmon hepatocytes (Duan et al 1993). Meanwhile, cortisol inhibited igf1 expression in the liver both with and without exogenous Gh induction.…”

Section: Endocrine and Paracrine Mechanisms Of Actionsupporting

confidence: 59%

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Distinct hormonal regulation of Na+,K+-atpase genes in the gill of Atlantic salmon (Salmo salar L.)

Tipsmark

Madsen²

2009

Journal of Endocrinology

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It has recently become evident that maintenance of ionic homoeostasis in euryhaline salmonids involves a reciprocal shift in expression of two isoforms of the gill Na+,K+-atpase α-subunit when the surrounding salinity changes. The present study investigated the regulation of this shift between the α1a (freshwater (FW) isoform) and the α1b (seawater (SW) isoform) by cortisol, Gh, prolactin (Prl) and Igf 1. Injection with cortisol into FW salmon increased α1a expression, while Gh had no effect. Conversely, both cortisol and Gh stimulated α1b expression, and a significant synergy was observed. igf1 expression was increased by Gh in both gill and liver, and inhibited by cortisol in the liver. Gill igf1 and gh receptor expression increased in response to cortisol. Injection with Prl into SW salmon compromised their hypo-osmoregulatory performance, selectively reduced the expression of the α1b isoform and decreased enzymatic Na+,K+-atpase activity in the gill. Cortisol and Prl reduced gill and liver igf1 expression, and both hormones stimulated gill igf1 receptor expression. In a short-term experiment with incubation of FW gill cell suspensions, cortisol stimulated α1a and α1b expression, while Igf1 stimulated only α1b. The data elaborate our understanding of Prl and Gh as being antagonists in the control of gill ion regulation, and support a dual role for Gh involving endocrine and paracrine Igf1 action. Gh and Prl may be the decisive stimuli that direct cortisol-aided mitochondrion-rich cell development into either secretory or absorptive types.

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Section: Endocrine and Paracrine Mechanisms Of Actionsupporting

confidence: 76%

Section: Endocrine and Paracrine Mechanisms Of Actionsupporting

confidence: 59%

Distinct hormonal regulation of Na+,K+-atpase genes in the gill of Atlantic salmon (Salmo salar L.)

Tipsmark

Madsen²

2009

Journal of Endocrinology

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Section: Discussionmentioning

confidence: 99%

“…Although the osmoregulatory physiology of fhm is unknown, in other teleost species igf1 mRNA has been identified in osmoregulatory organs (gill and kidney), and osmoregulatory challenges increase its expression (Sakamoto & Hirano 1993). Furthermore, there is evidence that IGF-I (both plasma and local) is a hormonal mediator of the hypo-osmoregulatory actions of GH (McCormick et al 1991, Madsen & Bern 1993, Sakamoto & Hirano 1993. Previous studies have reported that E 2 , and other environmental oestrogens, impact on osmoregulation both in salmonid (Madsen et al 1997, Stoffel et al 2000, Arsenault et al 2004, McCormick et al 2005) and non-salmonid (Vijayan et al 2001) species, and suppressed plasma levels of IGF-I were identified as the likely mechanism (McCormick et al 2005).…”

Section: Discussionmentioning

confidence: 99%

“…Growth hormone (GH), synthesised predominantly by the somatotrophs of the anterior pituitary, is best known for its growth-promoting capabilities (Cavari et al 1993), which are believed to be initiated principally through an intimate association with hepatic insulinlike growth factor-I (IGF-I), following GH-binding to membrane-bound GH receptors (GHRs) (reviewed in Kopchick & Andry 2000). However, GH participates in almost all major physiological processes in fish including osmo-and iono-regulation (Sakamoto & Hirano 1993), immune function (Perez-Sanchez 2000), reproduction (LeGac et al 1993) and behaviour (Bjornsson 1997). Furthermore, both GH and IGF-I additionally function in an autocrine/paracrine manner and independently of one another in some target tissues (Jones & Clemmons 1995, Harvey et al 1998, Butler & Le Roith 2001.…”

Section: Introductionmentioning

confidence: 99%

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Multiple molecular effect pathways of an environmental oestrogen in fish

Filby¹,

Thorpe²,

Tyler³

2006

Journal of Molecular Endocrinology

129

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Complex interrelationships in the signalling of oestrogenic effects mean that environmental oestrogens present in the aquatic environment have the potential to disrupt physiological function in fish in a more complex manner than portrayed in the present literature. Taking a broader approach to investigate the possible effect pathways and the likely consequences of environmental oestrogen exposure in fish, the effects of 17b-oestradiol (E 2 ) were studied on the expression of a suite of genes which interact to mediate growth, development and thyroid and interrenal function (growth hormone GH (gh), GH receptor (ghr ), insulin-like growth factor (IGF-I) (igf1), IGF-I receptor (igf1r ), thyroid hormone receptors-a (thra) and -b (thrb) and glucocorticoid receptor (gr )) together with the expression analyses of sex-steroid receptors and ten other genes centrally involved in sexual development and reproduction in fathead minnow (fhm; Pimephales promelas). Exposure of adult fhm to 35 ng E 2 /l for 14 days induced classic oestrogen biomarker responses (hepatic oestrogen receptor 1 and plasma vitellogenin), and impacted on the reproductive axis, feminising 'male' steroidogenic enzyme expression profiles and suppressing genes involved in testis differentiation. However, E 2 also triggered a cascade of responses for gh, ghr, igf1, igf1r, thra, thrb and gr in the pituitary, brain, liver, gonad and gill, with potential consequences for the functioning of many physiological processes, not just reproduction. Molecular responses to E 2 were complex, with most genes showing differential responses between tissues and sexes. For example, igf1 expression increased in brain but decreased in gill on exposure to E 2 , and responded in an opposite way in males compared with females in liver, gonad and pituitary. These findings demonstrate the importance of developing a deeper understanding of the endocrine interactions for unravelling the mechanisms of environmental oestrogen action and predicting the likely health consequences.

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Quantitation of IGF-I, IGF-II, and multiple insulin receptor family member messenger RNAs during embryonic development in rainbow trout

Greene

Chen

1999

Mol. Reprod. Dev.

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Expression of insulin-like growth factor I gene in osmoregulatory organs during seawater adaptation of the salmonid fish: possible mode of osmoregulatory action of growth hormone.

Abstract: Growth hormone has been shown to contribute to seawater adaptation of salmonid fishes. The growth influence of growth hormone is mediated largely by hepatic

Cited by 159 publications

References 51 publications

Distinct hormonal regulation of Na+,K+-atpase genes in the gill of Atlantic salmon (Salmo salar L.)

Distinct hormonal regulation of Na+,K+-atpase genes in the gill of Atlantic salmon (Salmo salar L.)

Multiple molecular effect pathways of an environmental oestrogen in fish

Quantitation of IGF-I, IGF-II, and multiple insulin receptor family member messenger RNAs during embryonic development in rainbow trout

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