OBJECTIVE: Whereas there seems to be little, if any, circadian variation in circulating concentrations of IGF-I and IGFBP-3 in healthy subjects, there are conflicting reports on this issue in GH-deficient patients treated with GH as a daily subcutaneous injection. We have therefore investigated the 24-hour serum profiles of IGF-I and IGFBP-3 concentrations after one week and more than one year of GH treatment. PATIENTS: Eleven subjects, with adult onset GH deficiency mainly caused by pituitary adenomas were included in the study. DESIGN AND MEASUREMENTS: In an open study, six subjects (three women and three men; age (+/-SEM) 41.2 +/- 3.9 years) were investigated after one week of GH therapy and five subjects (three women and two men; age (+/-SEM) 61.4 +/- 3.3 years) were investigated after 13-40 months of GH therapy. The GH injections were given at 2000 h. The subjects were hospitalized for 24-hour blood sampling at 1-hour intervals and serum concentrations of GH, IGF-I and IGFBP-3 were determined. RESULTS: There was a significant diurnal variation in serum IGF-I and IGFBP-3 concentrations both in the subjects who had received GH for one week and in those who had received GH treatment for more than one year. The serum concentrations of IGF-I and IGFBP-3 were highest in the morning and lowest during night-time and early morning. The molar IGF-I/IGFBP-3 ratio varied significantly with time in both groups of patients in a similar way as IGF-I and IGFBP-3 indicating a more pronounced variation in IGF-I compared with IGFBP-3 in response to the GH therapy. CONCLUSION: Significant diurnal variations in serum IGF-I and IGFBP-3 concentrations occur after one week and more than one year of GH treatment with daily subcutaneous injections. The results indicate that the free fraction of IGF-I may exhibit a diurnal variation.
OBJECTIVE: Whereas there seems to be little, if any, circadian variation in circulating concentrations of IGF-I and IGFBP-3 in healthy subjects, there are conflicting reports on this issue in GH-deficientpatients treated with GH as a daily subcutaneous injection. We have therefore investigated the 24-hour serum profiles of IGF-I and IGFBP-3 concentrations after one week and more than one year of GH treatment. PATIENTS: Eleven subjects, with adult onset GH deficiency mainly caused by pituitary adenomas were included in the study. DESIGN AND MEASUREMENTS: In an open study, six subjects (three women and three men; age (+/-SEM) 41.2 +/- 3.9 years) were investigated after one week of GH therapy and five subjects (three women and two men; age (+/-SEM) 61.4 +/- 3.3 years) were investigated after 13-40 months of GH therapy. The GH injections were given at 2000 h. The subjects were hospitalized for 24-hour blood sampling at 1-hour intervals and serum concentrations of GH, IGF-I and IGFBP-3 were determined. RESULTS: There was a significant diurnal variation in serum IGF-I and IGFBP-3 concentrations both in the subjects who had received GH for one week and in those who had received GH treatment for more than one year. The serum concentrations of IGF-I and IGFBP-3 were highest in the morning and lowest during night-time and early morning. The molar IGF-I/IGFBP-3 ratio varied significantly with time in both groups of patients in a similar way as IGF-I and IGFBP-3 indicating a more pronounced variation in IGF-I compared with IGFBP-3 in response to the GH therapy. CONCLUSION: Significant diurnal variations in serum IGF-I and IGFBP-3 concentrations occur after one week and more than one year of GH treatment with daily subcutaneous injections. The results indicate that the free fraction of IGF-I may exhibit a diurnal variation.
Authors: S Savastano; A Barbato; C Di Somma; B Guida; G Pizza; L Barrea; S Avallone; M Schiano di Cola; P Strazzullo; A Colao Journal: J Endocrinol Invest Date: 2012-07-09 Impact factor: 4.256
Authors: A Colao; S Spiezia; C Di Somma; R Pivonello; P Marzullo; F Rota; T Musella; R S Auriemma; M C De Martino; G Lombardi Journal: J Endocrinol Invest Date: 2005-05 Impact factor: 4.256