[Relationship between immunoreactive insulin and plasma somatomedin-C/insulin-like growth factor-I concentration in...

Childhood obesity may be characterised by basal and reactive hyperinsulinemia, reduced growth hormone (HGH) responses to various provocative stimuli and increased plasma concentration of somatomedine-C/insulin-like growth factor-I (SM-C/IGF-I). For this reason the relationship between the degree of obesity (i. e. BMI), serum immunoreactive insulin (IRI) and plasma SM-C/IGF-I was investigated in children with obesity (n = 26, age: 13.0 +/- 0.97 years, BMI: 32.8 +/- 5.3 kg/m2). SM-C/IGF-I was increased in obese children compared to the normal range of this age. Significant positive correlations were found between BMI and IRI, between BMI and SM-C/IGF-I, and between IRI and SM-C/IGF-I. These results suggest that SM-C/IGF-I production in obesity is regulated by IRI dependent on BMI and this regulating effect of insulin may be important in obesity since HGH production to provocative stimuli is reduced.