Relationship between insulin sensitivity and IGF-I sensitivity in low birth weight prepubertal children.
BACKGROUND
Insulin-like growth factor-I (IGF-I) and insulin are structurally related proteins with similar receptors and signal transduction systems.


OBJECTIVE
We postulate that some low birth weight (LBW) children may have decreased sensitivity to both insulin and IGF-I.


METHODS
We studied 48 prepubertal LBW children aged 7.6 +/- 2.4 years. Insulin sensitivity was determined using an oral glucose tolerance test, and IGF-I sensitivity was assessed by determining nocturnal GH concentrations at baseline and after administration of recombinant human IGF-I/IGFBP-3 complex.


RESULTS
Children were classified into quartiles of insulin sensitivity based on their glucose AUC/insulin AUC index. Children in the lowest quartile of insulin sensitivity exhibited a lower IGF-I sensitivity after administration of the rhIGF-I/rhIGFBP-3 complex compared to children in the highest quartile of insulin sensitivity (percent change in GH AUC: -44.2 +/- 5.7 vs. -21.6 +/- 6.8, p < 0.05).


CONCLUSIONS
LBW children in the lowest quartile of insulin sensitivity exhibited a lower pituitary GH response to the administration of rhIGF-I/rhIGFBP-3. Our findings suggest that reduced sensitivity to insulin and IGF-I may coexist in some prepubertal LBW children.
Institute of Maternal and Child Research, University of Chile, Santiago, Chile.
Rossana
R
Román
German
G
Iñiguez
Teresa
T
Salazar
Alejandra
A
Avila
Alvaro
A
Barrera
Verónica
V
Mericq
Kenneth M
KM
Attie
Fernando
F
Cassorla
D002648:Child; D002675:Child, Preschool; D005260:Female; D005951:Glucose Tolerance Test; D006130:Growth Disorders / Q000209:etiology; D019382:Human Growth Hormone / Q000097:blood; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D007333:Insulin Resistance / Q000502:physiology*; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000502:physiology*; D008297:Male; D011994:Recombinant Proteins
C515497:IGFBP3 protein, human; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D011994:Recombinant Proteins; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I