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Correlation between cortisol and insulin‐like growth factor‐binding proteins (IGFBPs) under physiological conditions in children
Author(s) -
Martinelli Jr Carlos E.,
Yateman Martin E.,
Cotterill Andrew M.,
Moreira Ayrton C.,
CamachoHübner Cecilia
Publication year - 1999
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1046/j.1365-2265.1999.00724.x
Subject(s) - endocrinology , medicine , circadian rhythm , insulin , insulin like growth factor binding protein , hydrocortisone , negative correlation , growth hormone , positive correlation , correlation , insulin like growth factor , hormone , biology , chemistry , growth factor , receptor , geometry , mathematics
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. DESIGN AND PATIENTS 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. MEASUREMENTS 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. CONCLUSION 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.