title: Correlation between cortisol and insulin-like growth factor-binding proteins (IGFBPs) under physiological conditions in children.
abstract: OBJECTIVE
  A positive correlation between 24-h spontaneous growth hormone (GH) and cortisol secretion was previously reported in children. This observation prompted us to examine the relationship between physiological diurnal cortisol variation and the levels of insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) under physiological conditions.
  
  
  METHODS
  Starting at 0800 h, blood was sampled every 20 minutes over 24 h for measurement of GH and cortisol concentration in nine non-GH- deficient boys as part of a protocol for the investigation of short stature.
  
  
  METHODS
  IGFBP-1 and insulin were measured in samples drawn every 4 h over the 24-h period while IGF-I, IGF-II, IGFBP-2 and IGFBP-3 were determined in samples collected at the end of the study.
  
  
  RESULTS
  No correlation was observed between IGF-I or IGF-II and mean cortisol levels. IGFBP-1 concentrations showed a marked circadian variation that was superimposed on the circadian rhythm for cortisol while a significant positive correlation was found for single point measurements between IGFBP-1 concentrations and cortisol levels measured in the same sample (r = 0.53) or at the preceding 20 minutes (r = 0.43), 40 minutes (r = 0.47) and 2 h (r = 0.38), suggesting an interplay between cortisol and IGFBP-1. A negative correlation (r = - 0.54) was found between IGFBP-1 and insulin levels determined in the same sample. A negative correlation (r = - 0.93) was also found between IGFBP-2 levels and mean cortisol concentrations during the preceding 12 h. No correlation was observed between plasma IGFBP-3 measured by IRMA and mean cortisol levels.
  
  
  CONCLUSIONS
  Our data indicate a clear correlation between cortisol and IGFBP-1 and IGFBP-2 levels. Thus, the interplay of spontaneous GH and cortisol secretion in children may involve changes in IGFBP-1 and IGFBP-2 levels.
authors.affiliation: Departments of Endocrinology and Paediatrics, St. Bartholomew's Hospital, London, UK; Departments of Paediatrics and Medicine, Faculty of Medicine of Ribeirão Preto, Brazil.
authors.forename: C E
authors.initials: CE
authors.lastname: Martinelli
authors.forename: M E
authors.initials: ME
authors.lastname: Yateman
authors.forename: A M
authors.initials: AM
authors.lastname: Cotterill
authors.forename: A C
authors.initials: AC
authors.lastname: Moreira
authors.forename: C
authors.initials: C
authors.lastname: Camacho-Hübner
mesh_terms: D000293:Adolescent; D019540:Area Under Curve; D002648:Child; D002940:Circadian Rhythm; D006130:Growth Disorders / Q000097:blood*; D013006:Growth Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007328:Insulin / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D018971:Insulin-Like Growth Factor Binding Protein 2 / Q000097:blood; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood; D018969:Insulin-Like Growth Factor Binding Proteins / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007335:Insulin-Like Growth Factor II / Q000032:analysis; D016014:Linear Models; D008297:Male
chemical_list: D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D018971:Insulin-Like Growth Factor Binding Protein 2; D018972:Insulin-Like Growth Factor Binding Protein 3; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013006:Growth Hormone; D006854:Hydrocortisone