Related Experiment Video
Updated: May 30, 2026

Homogeneous Time-resolved Förster Resonance Energy Transfer-based Assay for Detection of Insulin Secretion
Published on: May 10, 2018
Insulin-like growth factor I: pros and cons of a bioassay
1Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands. j.a.m.j.l.janssen@erasmusmc.nl
Background:
Insulin-like growth factor I (IGF-I) immunoassays are primarily used to estimate IGF-I status. Recently an IGF-I-specific kinase receptor activation assay (KIRA) was developed as an alternative method for measuring IGF-I bioactivity. When compared with IGF-I immunoassays, the IGF-I KIRA has the theoretical advantage of measuring the net effects of IGF-binding proteins on IGF-I receptor activation. The IGF-I KIRA is sensitive and specific and has, for a bioassay, a very low intra- and inter-assay coefficient of variation (<7 and <15%, respectively). Several studies have shown that the IGF-I KIRA is more sensitive than IGF-I immunoassays for detecting differences in clinical state. In addition, the IGF-I KIRA seems superior to IGF-I immunoassays for monitoring acute effects of therapeutic interventions.
Conclusions:
It is not known if IGF-I KIRA is superior to IGF-I immunoassays for evaluating the efficacy of growth hormone (GH) treatment for GH deficiency and of GH receptor antagonist treatment for acromegaly. However, IGF-I KIRA undoubtedly will provide new insights into the factors that regulate IGF-I bioactivity in the circulation in both healthy and diseased states.
Related Concept Videos
Insulin: The Receptor and Signaling Pathways
Insulin: Dosing Regimen and Adverse Effects
The basal dose constitutes about 40%-50% of the total daily dose, with the rest as premeal insulin. The mealtime insulin dose should mirror...
Hormones Regulating Blood Glucose
In addition to accelerating glucose uptake and utilization, insulin has...
Glucagon-like Receptor Agonists
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...
Production of Pharmaceuticals

