INSULIN‐LIKE GROWTH FACTOR I (IGF‐I) IN HEALTHY CHILDREN, ADOLESCENTS AND ADULTS AS DETERMINED BY A RADIOIMMUNOASSAY SPECIFIC FOR THE SYNTHETIC 53–70 PEPTIDE REGION

Publisher Website
Google Scholar
Abstract
SUMMARY: A radioimmunoassay (RIA) specific for the synthetic 53–70 peptide region of human insulin‐like growth factor I (IGF‐I) was used to determine IGF‐I in the serum of 191 healthy newborns, children and adolescents and in 26 adults. The results compare favourably with reported values obtained using RIA systems for the native IGF‐I molecule. Intra‐ and inter‐assay CV were 3.3 and 7.2% respectively. In childhood, mean ± SD IGF‐I levels rise from 60 ± 3.5 nmol/l in newborns to 16.5±4.0 nmol/l at 8–11 years in both sexes. At the onset of puberty, IGF‐I levels in females (24.9 ± 6.6 nmol/l) are significantly (P > 0.005) higher than in males (17.2 ± 4.2 nmol/l). With further pubertal development IGF‐I levels continue to rise, reaching peak values at pubertal stage P4 (40.6 ± 4.5 nmol/l in males, 42.8 ± 5.1 nmol/l in females) and decline thereafter to lower values during adulthood: 16.5 ± 5.8 nmol/l (males) and 24.2 ± 7.0 nmol/l (females) (P > 0.001). In pubertal males, IGF‐I correlates significantly with height (r= 0.66, P < 0.001), bone age (r= 0.69, P > 0.001) and growth velocity (r= 0.64, P= 0.025) as well as with testosterone levels (r= 0.69, P < 0.001). In pubertal females a significant correlation is found between IGF‐I and height (r= 0.55, P < 0.020). The ready availability of a simple, precise and reproducible IGF‐I RIA, should contribute much to evaluating the importance of IGF‐I measurements in normal growth and in the diagnosis and therapy of various growth disorders.

This publication has 18 references indexed in Scilit: