Free and Protein-Bound Insulin-like Growth Factor-I (IGF-I) and IGF-Binding Proteins in Plasma of Coho Salmon, Oncorhynchus kisutch

Shimizu, Munetaka; Swanson, Penny; Dickhoff, Walton W.

doi:10.1006/gcen.1999.7328

Cited by 116 publications

(57 citation statements)

References 32 publications

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“…They were maintained in recirculated fresh water in circular fiberglass tanks under natural photoperiod; flow rate was 25 l/min; temperature ranged from 10·5 to 13·0 C. Fish were fed standard rations (0·6-1·0% body weight/day) of a commercial diet (Biodiet Grower; Bioproducts Inc., Warrenton, OR, USA). Some of the 2-year-old coho salmon were injected twice with salmon GH at a dose of 0·1 µg/g body weight or saline, and sampled 24 h after the second injection (48 h after first injection) as described in Shimizu et al (1999). Other groups were fasted or fed freely for 1 month (Shimizu et al 1999).…”

Section: Fishmentioning

confidence: 99%

“…Some of the 2-year-old coho salmon were injected twice with salmon GH at a dose of 0·1 µg/g body weight or saline, and sampled 24 h after the second injection (48 h after first injection) as described in Shimizu et al (1999). Other groups were fasted or fed freely for 1 month (Shimizu et al 1999). Blood was withdrawn by cutting the caudal peduncle and letting blood flow into a heparinized glass tube.…”

Section: Fishmentioning

confidence: 99%

“…In fish, IGFBPs corresponding to mammalian IGFBP-1 and -2 have been cloned in zebrafish (Danio rerio; Duan et al 1999) and gilthead sea bream (Sparus aurata, Funkenstein et al 2002), and an almost complete sequence has been reported for tilapia (Oreochromis mossambicus) IGFBP-3 (Cheng et al 2002). Multiple IGFBPs have been detected in fish plasma/serum by Western ligand blotting using labeled IGF-I and have been shown to be controlled by hormones, nutritional status and stress (Kelley et al 1992, Niu & Le Bail 1993, Siharath et al 1995, 1996, Shimizu et al 1999, Park et al 2000. Duan and co-workers showed that fish IGFBPs expressed in animal cells or purified from culture medium inhibit IGF-stimulated DNA synthesis in vitro (Duan et al 1999, Bauchat et al 2001.…”

Section: Introductionmentioning

confidence: 99%

“…In salmon, at least three IGFBPs with molecular masses of 41, 28 and 22 kDa exist in plasma. The 41 kDa IGFBP is most likely the salmon IGFBP-3, since it has a molecular mass similar to mammalian IGFBP-3 and its plasma levels are influenced by growth hormone (GH) treatment and fasting, as is mammalian IGFBP-3 (Shimizu et al 1999).…”

Section: Introductionmentioning

confidence: 99%

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Development of an RIA for salmon 41 kDa IGF-binding protein

Shimizu¹,

Hara²,

Dickhoff³

2003

Journal of Endocrinology

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Salmon plasma contains at least three IGF-binding proteins (IGFBPs) with molecular masses of 41, 28 and 22 kDa. The 41 kDa IGFBP is similar to mammalian IGFBP-3 in size, type of glycosylation and physiological responses. In this study, we developed an RIA for the 41 kDa IGFBP. The 41 kDa IGFBP purified from serum was used for antibody production and as an assay standard. Binding of three different preparations of tracer were examined: 125 I-41 kDa IGFBP, I-IGF-I was not affected by added IGFs, and therefore it was chosen for the tracer in the RIA. Plasma 41 kDa IGFBP levels measured by RIA were increased by GH treatment (178·9 4·9 ng/ml) and decreased after fasting (95·0 7·0 ng/ml). The molarities of plasma 41 kDa IGFBP and total IGF-I were comparable, and they were positively correlated, suggesting that salmon 41 kDa IGFBP is a main carrier of circulating IGF-I in salmon, as is mammalian IGFBP-3 in mammals. During the parr-smolt transformation (smoltification) of coho salmon, plasma 41 kDa IGFBP levels showed a transient peak (182·5 10·3 ng/ml) in March and stayed relatively constant thereafter, whereas IGF-I showed peak levels in March and April. Differences in the molar ratio between 41 kDa IGFBP and IGF-I possibly influence availability of IGF-I in the circulation during smoltification.

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Section: Fishmentioning

confidence: 99%

Section: Fishmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development of an RIA for salmon 41 kDa IGF-binding protein

Shimizu¹,

Hara²,

Dickhoff³

2003

Journal of Endocrinology

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“…IGF-I exerts its growth-promoting action through endocrine, paracrine and autocrine mechanisms [26,31]. In mammals, IGF-I is 4 [38,39] …”

Section: Introductionmentioning

confidence: 99%

Circulating salmon 41-kDa insulin-like growth factor binding protein (IGFBP) is not IGFBP-3 but an IGFBP-2 subtype

Shimizu¹,

Suzuki²,

Horikoshi³

et al. 2011

General and Comparative Endocrinology

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In vertebrates, most circulating insulin-like growth factor (IGF) is bound to multiple forms of IGF-binding proteins (IGFBPs) that differ both structurally and functionally. In mammals, the largest reservoir of IGF in the circulation comes from a large (150kDa) ternary complex comprised of IGF bound to IGFBP-3, which is bound to an acid label subunit (ALS), and this variant of IGFBP is regulated by growth hormone (GH) and feed intake. Although multiple variants of IGFBPs ranging from 20 to 50 kDa have been found in fishes, no ternary complex is present and it has been assumed that the majority of circulating IGF is bound to fish IGFBP-3. Consistent with this assumption is previous work in salmon showing the presence of a 41-kDa IGFBP that is stimulated by GH, decreases with fasting and increases with feeding. However, the hypothesis that the salmon 41-kDa IGFBP is structurally homologous to mammalian IGFBP-3 has not been directly tested. To address this issue, we cloned cDNAs for several Chinook salmon IGFBPs, and found that the cDNA sequence of the 41-kDa IGFBP is most similar to that of mammalian IGFBP-2 and dissimilar to IGFBP-3. We found an additional IGFBP (termed IGFBP-2a) with high homology to mammalian IGFBP-2. These results demonstrate that salmon 41-kDa IGFBP is not IGFBP-3, but a paralog of IGFBP-2 (termed IGFBP-2b). Salmon IGFBP-2s are also unique in terms of having potential N-glycosylation sites and splice variants. Additional research on non-mammalian IGFBPs is needed to fully understand the molecular/functional evolution of the IGFBP family and the significance of the ternary complex in vertebrates

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Gene expression of growth hormone family and glucocorticoid receptors, osmosensors, and ion transporters in the gill during seawater acclimation of Mozambique tilapia, Oreochromis mossambicus

et al. 2010

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This study characterized endocrine and ionoregulatory responses accompanying seawater (SW) acclimation in Mozambique tilapia (Oreochromis mossambicus). Changes in plasma hormones and gene expression of hormone receptors, putative osmosensors, and ion transporters in the gill were measured. Transfer of freshwater (FW)-acclimated tilapia to SW resulted in a marked elevation in plasma osmolality and a significant rise in plasma growth hormone (GH) levels at 12 hr and 14 days after transfer. Significant reductions in plasma prolactin (PRL(177) and PRL(188)) levels also occurred in SW-transferred fish; no effect of transfer upon plasma cortisol or insulin-like growth factor I was observed. Gene expression of GH receptor increased strongly 6 hr after transfer, whereas PRL receptor was lower than controls at 12 hr. By contrast, mRNA levels of somatolactin and glucocorticoid receptors were unaffected by SW transfer. Osmotic stress transcription factor 1 mRNA levels rose significantly between 3 and 12 hr, whereas the calcium-sensing receptor was unaffected. Aquaporin-3 gene expression was strongly down-regulated during SW acclimation from 12 hr until the conclusion of the experiment. Na(+)/K(+)/2Cl(-) cotransporter gene expression increased significantly 3 hr after transfer, whereas expression of Na(+)/Cl(-) cotransporter, specific to FW-type chloride cells, declined by 6 hr into SW acclimation. The response of Na(+)/H(+) exchanger was less pronounced, but showed a similar pattern to that of the Na(+)/Cl(-) cotransporter. These results suggest that acquisition of hyposmoregulatory mechanisms in Mozambique tilapia entails the coordinated interaction of systemic hormones with local factors in the gill, including hormone receptors, ion transporters, and osmosensors.

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Free and Protein-Bound Insulin-like Growth Factor-I (IGF-I) and IGF-Binding Proteins in Plasma of Coho Salmon, Oncorhynchus kisutch

Cited by 116 publications

References 32 publications

Development of an RIA for salmon 41 kDa IGF-binding protein

Development of an RIA for salmon 41 kDa IGF-binding protein

Circulating salmon 41-kDa insulin-like growth factor binding protein (IGFBP) is not IGFBP-3 but an IGFBP-2 subtype

Gene expression of growth hormone family and glucocorticoid receptors, osmosensors, and ion transporters in the gill during seawater acclimation of Mozambique tilapia, Oreochromis mossambicus

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