open access

https://hdl.handle.net/2115/39000

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

RIA for salmon IGFBP

英語

smoltification

2003-08

Society for Endocrinology

Journal of Endocrinology

178(2)

275-283

Salmon plasma contains at least three insulin-like growth factor 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 a radioimmunoassay (RIA) for the 41-kDa IGFBP. The 41-kDa IGFBP purified from serum was used for antibody production and assay standard. Binding of three different preparations of tracer were examined; 125I-41-kDa IGFBP, 125I-41-kDa IGFBP cross-linked with IGF-I (125I-41-kDa IGFBP/IGF-I) and 41-kDa IGFBP/125I-IGF-I. Only binding of 41-kDa IGFBP/125I-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 growth hormone 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.

学術雑誌論文

Accepted Manuscript

Disclaimer. This is not the definitive version of record of this article. This manuscript has been accepted for publication in Journal of Endocrinology, but the version presented here has not yet been copy edited, formatted or proofed. Consequently, the Society for Endocrinology accepts no responsibility for any errors or omissions it may contain. The definitive version is now freely available at 10.1677/joe.0.1780275 © 2003 Society for Endocrinology.

0022-0795

1479-6805

AA00697140