Integrity of the growth hormone/insulin-like growth factor system is maintained in patients with chronic fatigue syndrome.
GH deficiency states and chronic fatigue syndrome (CFS) share several characteristics, and preliminary studies have revealed aspects of GH dysfunction in CFS. This study assessed indexes of GH function in 37 medication-free CFS patients without comorbid psychiatric illness and 37 matched healthy controls. We also assessed GH function before and after treatment with low dose hydrocortisone, which has been shown recently to reduce fatigue in CFS. We measured basal levels of serum insulin-like growth factor I (IGF-I), IGF-II, IGF-binding protein-1 (IGFBP-1), IGFBP-2 and IGFBP-3 together with 24-h urinary GH excretion. We also performed 2 dynamic tests of GH function: a 100-microg GHRH test and an insulin stress test using 0.15 U/kg BW insulin. There were no differences between patients and controls in basal levels of IGF/IGFBP or in urinary GH excretion. GH responses to both the GHRH test and the insulin stress test were no different in patients and controls. CFS patients did have a marginally reduced suppression of IGFBP-1 during the insulin stress test. Hydrocortisone treatment had no significant effect on any of these parameters. There is no evidence of GH deficiency in CFS. At the doses used, hydrocortisone treatment appears to have little impact on GH function.
Cleare
A J
AJ
Department of Psychological Medicine, Guy's King's and St. Thomas' School of Medicine, and the Institute of Psychiatry, London, United Kingdom. a.cleare@iop.kcl.ac.uk
Sookdeo
S S
SS
Jones
J
J
O'Keane
V
V
Miell
J P
JP
D000328:Adult; D005080:Exercise Test; D015673:Fatigue Syndrome, Chronic / Q000188:drug therapy / Q000503:physiopathology*; D005260:Female; D013007:Growth Hormone-Releasing Hormone; D019382:Human Growth Hormone / Q000097:blood / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000627:therapeutic use; D007328:Insulin; 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 / Q000502:physiology*; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology*; D007335:Insulin-Like Growth Factor II / Q000032:analysis / Q000502:physiology*; D008297:Male
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; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D013007:Growth Hormone-Releasing Hormone; D006854:Hydrocortisone