Insulin-like growth factor binding protein-I levels are strongly associated with insulin sensitivity and obesity in early pubertal children.
In conditions associated with insulin resistance, insulin-like growth factor binding protein-I (IGFBP-I) levels have been shown to correlate inversely with insulin levels. Puberty is associated with insulin resistance and thus provides a model for comparing the relationship of IGFBP-I to both insulin levels and measures of insulin sensitivity. Our study population consisted of 104 healthy pubertal children, age 9.8-14.6 yr. Each subject had his/her insulin sensitivity (Si) assessed by the modified minimal model of Bergman, which employs a frequently sampled i.v. glucose tolerance test. Results showed that IGFBP-I levels were significantly higher in boys than in pubertally matched girls (P < 0.01). There was a strong positive correlation between IGFBP-I levels and Si (r = 0.65, P < 0.0001) and a weaker negative correlation with fasting insulin levels (r = -0.38, P < 0.0001). An inverse relationship was also found between IGFBP-I levels and body mass index (r = -0.46, P < 0.0001) and with IGF-I levels (girls only, r = -0.41, P < 0.003). Consequently, insulin sensitivity, obesity, and IGF-I are important predictors of IGFBP-I levels in pubertal children. It is possible that insulin-mediated suppression of IGFBP-I in obese children may increase free IGF-I levels and thus contribute to somatic growth. The same mechanism may operate in pubertal children, where insulin resistance and growth acceleration occur simultaneously.
Travers
S H
SH
Department of Pediatrics, Children's Hospital, Denver, Colorado 80218, USA.
Labarta
J I
JI
Gargosky
S E
SE
Rosenfeld
R G
RG
Jeffers
B W
BW
Eckel
R H
RH
D000273:Adipose Tissue; D000293:Adolescent; D001823:Body Composition; D015992:Body Mass Index; D002648:Child; D005215:Fasting; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D009765:Obesity / Q000097:blood*; D011627:Puberty
D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D007334:Insulin-Like Growth Factor I