Developmental Changes in Serum Levels of Free and Total Insulin-Like Growth Factor I (IGF-I), IGF-Binding Protein-1 and -3, and the Acid-Labile Subunit in Rats**This work was supported by grants from the Danish Health Research Council (Grants 9602012 and 9700592), the Aarhus University-Novo Nordisk Center for Research in Growth and Regeneration (Danish Health Research Council Grant 9600822), the Institute of Experimental Clinical Research, University of Aarhus, the Novo Foundation, the Nordic Insulin Foundation, and the National Health and Medical Research Council of Australia (to R.C.B.)
| Autor: | Henning Grønbæk, C. Skjærbæk, Jan Frystyk, Allan Flyvbjerg, Hans Ørskov, Robert C. Baxter |
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| Rok vydání: | 1998 |
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| Zdroj: | Endocrinology. 139:4286-4292 |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/endo.139.10.6273 |
| Popis: | We have recently described a competitive binding assay for rat insulin-like growth factor-binding protein-3 (IGFBP-3) based on the ability of IGFBP-3 to form a ternary complex with the acid-labile subunit (ALS) in the presence of IGF-I. Using this assay we studied groups of male (n = 6) and female rats (n = 6) at 20, 30, 40, 50, 60, 80, and 130 days of age. Nonfasting serum levels of IGFBP-3 were compared with those of total (extractable) IGF-I (tIGF-I) and ALS as well as IGFBP-3 determined by ligand blotting. Additionally, we studied the relationship between ultrafiltered free IGF-I (fIGF-I) and immunoassayable IGFBP-1. IGFBP-3 was dependent on age only (P < 0.0001), but tended to be higher in males than in females (P= 0.06); between 20–130 days levels increased from 6.5 ± 1.7 to 73.6 ± 7.2 nmol/liter in males and from 5.4 ± 1.6 to 51.3 ± 8.0 nmol/liter in females. IGFBP-3 correlated positively with tIGF-I (r = 0.90; P < 0.0001), ALS (r = 0.92; P < 0.0001), and IGFBP-3, as determined by ligand blotting (... |
| Databáze: | OpenAIRE |
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