| Title: |
Normal values of circulating insulin-like growth factor-I bioactivity in the healthy population: Comparison with five widely used IGF-I immunoassays |
| Authors: |
Brugts, Michel; Ranke, MB; Hofland, Leo; van der Wansem, K (Katy); Weber, K; Frystyk, J; Lamberts, S.W.J.; Janssen, J.A.M.J.L. |
| Source: |
Brugts, M, Ranke, MB, Hofland, L, van der Wansem, K, Weber, K, Frystyk, J, Lamberts, S W J & Janssen, J A M J L 2008, 'Normal values of circulating insulin-like growth factor-I bioactivity in the healthy population: Comparison with five widely used IGF-I immunoassays', Journal of Clinical Endocrinology and Metabolism, vol. 93, no. 7, pp. 2539-2545. https://doi.org/10.1210/jc.2007-2454 |
| Publication Year: |
2008 |
| Subject Terms: |
/dk/atira/pure/keywords/researchprograms/AFL001000/EMCMM013901; name=EMC MM-01-39-01 |
| Description: |
Background: IGF-I immunoassays are primarily used to estimate IGF-I bioactivity. Recently an IGF-I-specific kinase receptor activation assay (KIRA) has been developed as an alternative method. However, no normative values have been established for the IGF-I KIRA. Objective: The objective of the study was to establish normative values for the IGF-I KIRA in healthy adults. Design: This was a cross-sectional study in healthy nonfasting blood donors. Study Participants: Participants included 426 healthy individuals (310 males, 116 females; age range 18-79 yr). Main Outcome Measures: IGF-I bioactivity determined by the KIRA was measured. Results were compared with total IGF-I, measured by five different IGF-I immunoassays. Results: Mean (+/- SD) IGF-I bioactivity was 423 (+/- 131) pmol/liter and decreased with age (beta = -3.4 pmol/liter.yr, P < 0.001). In subjects younger than 55 yr, mean IGF-I bioactivity was significantly higher in women than men. Above this age this relationship was inverse, suggesting a drop in IGF-I bioactivity after menopause. This drop was not reflected in total IGF-I levels. IGF-I bioactivity was significantly related to total IGF-I (r(s) varied between 0.46 and 0.52; P < 0.001). Conclusions: We established age-specific normative values for the IGF-I KIRA. We observed a significant drop in IGF-I bioactivity in women between 50 and 60 yr, which was not perceived by IGF-I immunoassays. The IGF-I KIRA, when compared with IGF-I immunoassays, theoretically has the advantage that it measures net effects of IGF-binding proteins on IGF-I receptor activation. However, it has to be proven whether information obtained by the IGF-I KIRA is clinically more relevant than measurements obtained by IGF-I immunoassays. |
| Document Type: |
article in journal/newspaper |
| File Description: |
application/pdf |
| Language: |
unknown |
| ISSN: |
0021-972X; 1945-7197 |
| Relation: |
info:eu-repo/semantics/altIdentifier/pmid/18397983; info:eu-repo/semantics/altIdentifier/pissn/0021-972X; info:eu-repo/semantics/altIdentifier/eissn/1945-7197 |
| DOI: |
10.1210/jc.2007-2454 |
| Availability: |
https://pure.eur.nl/en/publications/5da22d3d-93c1-462c-b743-cced77a82571; https://doi.org/10.1210/jc.2007-2454; https://pure.eur.nl/ws/files/46786134/jc.2007-2454v1.pdf; https://hdl.handle.net/1765/13710 |
| Rights: |
info:eu-repo/semantics/openAccess |
| Accession Number: |
edsbas.AD3743D1 |
| Database: |
BASE |