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The insulin-like growth factor-I receptor stimulating activity (IRSA) in health and disease.
- Source :
- Growth Hormone & IGF Research; Oct2019, Vol. 48, p16-28, 13p
- Publication Year :
- 2019
-
Abstract
- Determination of true IGF-I bioactivity in serum and other biological fluids is still a substantial challenge. The IGF-IR Kinase Receptor Activation assay (IGF-IR KIRA assay) is a novel tool to asses IGF-IR stimulating activity (IRSA) and has opened a new era in studying the IGF system. In this paper we discuss many studies showing that measuring IRSA by the IGF-IR KIRA assay often provides fundamentally different information about the IGF system than the commonly used total IGF-I immunoassays. With the IGF-IR KIRA assay phosphorylation of tyrosine residues of the IGF-IR is used as read out to quantify IRSA in unknown (serum) samples. The IGF-IR KIRA assay gives information about net overall effects of circulating IGF-I, IGF-II, IGFBPs and IGFBP-proteases on IGF-IR activation and seems especially superior to immunoreactive total IGF-I in monitoring therapeutic interventions. Although the IRSA as measured by the IGF-IR KIRA assay probably more closely reflects true bioactive IGF-I than measurements of total IGF-I in serum, the IGF-IR KIRA assay in its current form does not give information about all the post-receptor intracellular events mediated by the IGF-IR. Interestingly, in several conditions in health and disease IRSA measured by the IGF-IR KIRA assay is considerably higher in interstitial fluid and ascites than in serum. This suggests that both the paracrine (local) and endocrine (circulating) IRSA should be measured to get a complete picture about the role of the IGF system in health and disease. Unlabelled Image • Measuring IRSA by the IGF-I KIRA assay often provides fundamentally different information about the IGF system than total IGF-I immunoassays. • The IGF-IR KIRA assay seems especially superior to immunoreactive total IGF-I in monitoring therapeutic interventions. • IRSA has been found to be considerably higher in interstitial fluid and ascites than in serum. • Measurement of paracrine (local) and endocrine (circulating) IRSA is necessary to get a complete picture of the IGF system in health and disease. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 10966374
- Volume :
- 48
- Database :
- Supplemental Index
- Journal :
- Growth Hormone & IGF Research
- Publication Type :
- Academic Journal
- Accession number :
- 140248725
- Full Text :
- https://doi.org/10.1016/j.ghir.2019.08.001