Comparison Between Insulin-Like Growth Factor-I(IGF-I) and IGF Binding Protein-3(IGFBP-3) Measurement in the Diagnosis of Growth Hormone Deficiency.

Abstract

Abstract. To analyze the utility of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) radioimmunoassay in the diagnosis of growth hormone deficiency (GHD) we measured IGF-I and IGFBP-3 in sera from normal children (n=309), short children (n=99) and patients with GHD (n=73). In 80% and 93% of classical GHD (cGHD), IGF-I and IGFBP-3 levels, respectively, were below the age-related cutoff levels (lower limit). In 81% and 88% of normal short children (NS), IGF-I and IGFBP-3 levels, respectively, were above the age-related cutoff levels. Thus, both IGF-I and IGFBP-3 were good parameters for screening GHD. In contrast, in more than half of partial GHD (pGHD), either IGF-I or IGFBP-3 was above the age-related cutoff levels. The poor discrimination between patients with pGHD and NS by using these two parameters may be the result of their relatively similar GH levels, as compared to cGHD, or due to the limitations of GH stimulation tests. In about 80-90% of NS, IGF-I and IGFBP-3 were above the age-related cutoff levels at all ages. A hundred percent of cGHD under 10 years old had IGFBP-3 below the age-related cutoff levels, whereas 79% of cGHD under 10 years old had IGF-I below the age-related cutoff levels. Thus in the younger age groups, IGFBP-3 may be more sensitive than IGF-I. It may be because IGFBP-3 levels are relatively higher than those of IGF-I in younger subjects. IGFBP-3 may be less sensitive for diagnosing GHD in older children than in younger children because IGFBP-3 levels may also increase during puberty by mechanisms independent of the GH-IGF-I axis. There was a significant correlation between IGF-I and IGFBP-3 in all the subjects. However, IGF-I and IGFBP-3 classified subjects differently in 25% of patients with GHD and 19% of those with NS. This may reflect differences in daily coefficient of

Plasma Levels of Insulin-Like Growth Factor (IGF)-I, IGF-II and IGF-Binding Protein-3 in the Evaluation of Childhood Growth Hormone Deficiency

“…To our knowledge, only one report has been published on the value of IGF-I and IGFBP-3 in the prediction of growth response to GH therapy [16]. In this study, a negative relationship between IGFBP-3 and the increment in height velocity was found, but this was caused mainly by the subgroup of ‘complete’ GHD children (maximal GH levels after provocation <10 mU/l).…”

“…The serum concentrations of these proteins are GH-dependent and several studies have shown that low levels of serum IGF-I, IGF-II and IGFBP-3 and high serum IGFBP-2 levels may be predictive for GHD, although not all studies have come to similar conclusions [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21]. Theoretically, the biological response to GH treatment could be used as the final confirmation of the diagnosis of GHD, as children with severe GHD on the average accelerate their growth more than children with a less severe deficiency and considerably more than children with idiopathic short stature (ISS) [22].…”

Insulin-Like Growth Factor I Levels and the Diagnosis of Adult Growth Hormone Deficiency

“…IGF-I action is also critically modulated by specific binding proteins, among which IGF binding protein 3 (IGFBP-3) is the most abundant circulating form. IGFBP-3 is GH-dependent [15]and has been considered to be another marker of GH secretion, although it is less sensitive than IGF-I [8, 22, 23, 24, 25]. IGF-I is generally measured as total circulating levels, although free IGF-I levels can also be measured [12, 26].…”

Insulin-Like Growth Factors-Insulin-Like Growth Factor Binding Protein Axis and Diabetic Cotrol in Insulin- Dependent Diabetes Mellitus

“…Serum and plasma were obtained after 8-10 h fasting in the morning. In these subjects, the free form of IGF-I (free IGF-I), the total IGF-I (total IGF-I: free plus complexed form of IGF-I) , and IGFBP-3 were measured, as previously described [3,4]. The Zscores of free IGF-I, total IGF-I, and IGFBP-3 were calculated by using age-matched normal values [4, 5, our unpublished data].…”