title: The evolution of changes in immunoreactive serum insulin-like growth factors (IGFs), IGF-binding proteins, circulating growth hormone (GH) and GH-binding protein as a result of short-term dexamethasone treatment.
abstract: Inhibition of growth in man and laboratory animals by glucocorticoid treatment is well recognized, yet we have previously shown that glucocorticoids may paradoxically enhance GH secretion and increase serum insulin-like growth factor (IGF) levels. IGFs circulate bound to high-affinity binding proteins (IGFBPs) which modulate their actions, and circulating GH may be associated with two binding proteins (GHBPs) of which the high-affinity GHBP has been characterized and is structurally identical to the extracellular domain of the GH receptor. We have investigated the time-course of changes in GH, IGFs and their binding proteins induced by glucocorticoid treatment in normal male volunteers (n = 12, age range 22-31 years) sampled at 0800 h daily before and during treatment with dexamethasone (2 mg twice daily) for 5 days. In addition, subjects were sampled at 30-min intervals over 7-h periods (0730-1430 h) during the day prior to dexamethasone (day 0), on day 1 following the first dose of dexamethasone and on day 5 following the last dose of dexamethasone. Mean serum IGF-I rose over the initial 72 h and remained elevated at 96 h (297 +/- 11.5 compared with basal levels of 215.5 +/- 9.3 micrograms/l, P < 0.001) whereas IGF-II levels did not change (472.6 +/- 20.5 vs 450.3 +/- 21.7 micrograms/l, P = 0.97). There was a concomitant rise in serum IGFBP-3 from basal levels of 3.69 +/- 0.23 mg/l to a peak at 5 days of 4.16 +/- 0.21 (P = 0.003 vs day 1).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Medicine, King's College School of Medicine, London, UK.
authors.forename: J P
authors.initials: JP
authors.lastname: Miell
authors.forename: C R
authors.initials: CR
authors.lastname: Buchanan
authors.forename: M R
authors.initials: MR
authors.lastname: Norman
authors.forename: H G
authors.initials: HG
authors.lastname: Maheshwari
authors.forename: W F
authors.initials: WF
authors.lastname: Blum
mesh_terms: D000328:Adult; D002352:Carrier Proteins / Q000097:blood / Q000378:metabolism; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004334:Drug Administration Schedule; D013006:Growth Hormone / Q000097:blood*; D006801:Humans; D007328:Insulin / Q000097:blood; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D007335:Insulin-Like Growth Factor II / Q000378:metabolism; D008297:Male; D013002:Somatomedins / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D007328:Insulin; D018971:Insulin-Like Growth Factor Binding Protein 2; D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D003907:Dexamethasone; D013006:Growth Hormone; C051815:somatotropin-binding protein