title: Long-term effects of insulin-like growth factor (IGF)-I treatment on serum IGFs and IGF binding proteins in adolescent patients with growth hormone receptor deficiency.
abstract: OBJECTIVE
  The aim of this investigation was to study the effect of relatively high dose IGF-I therapy given for several months, on serum levels of IGF-I, IGF-II and IGFBP-3, and on IGF-I pharmacokinetics in patients with growth hormone insensitivity due to GH receptor dysfunction.
  
  
  METHODS
  Two adolescent subjects from Ecuador were treated with recombinant IGF-I at a dosage of 120 micrograms/kg s.c. twice daily, in combination with a GnRH analogue for 8 months.
  
  
  METHODS
  Serum was sampled at baseline and at 3-8 months, for determination of IGF-I, IGF-II and IGFBP-3 by radioimmunoassay, and for evaluation of IGFBPs and IGFBP-3 protease activity by Western ligand blot and protease assay, respectively.
  
  
  RESULTS
  Peak serum IGF-I levels ranged from 272 to 492 micrograms/l. Mean serum IGF-II levels were decreased concurrently with the increase in IGF-I. Serum IGFBP-3 levels failed to rise with prolonged IGF-I treatment. There was no apparent change in the half-life of IGF-I during the treatment period.
  
  
  CONCLUSIONS
  IGF-I administration does not increase serum levels of IGFBP-3 or significantly alter IGF-I pharmacokinetics.
authors.affiliation: Department of Pediatrics, Stanford University Medical School, CA, USA.
authors.forename: K F
authors.initials: KF
authors.lastname: Wilson
authors.forename: P J
authors.initials: PJ
authors.lastname: Fielder
authors.forename: J
authors.initials: J
authors.lastname: Guevara-Aguirre
authors.forename: P
authors.initials: P
authors.lastname: Cohen
authors.forename: O
authors.initials: O
authors.lastname: Vasconez
authors.forename: V
authors.initials: V
authors.lastname: Martinez
authors.forename: A
authors.initials: A
authors.lastname: Martinez
authors.forename: A L
authors.initials: AL
authors.lastname: Rosenbloom
authors.forename: R G
authors.initials: RG
authors.lastname: Rosenfeld
mesh_terms: D000293:Adolescent; D015153:Blotting, Western; D002352:Carrier Proteins / Q000097:blood*; D010450:Endopeptidases / Q000097:blood; D005260:Female; D006128:Growth / Q000187:drug effects; D006131:Growth Inhibitors / Q000097:blood*; D006207:Half-Life; D006801:Humans; D018969:Insulin-Like Growth Factor Binding Proteins; D007334:Insulin-Like Growth Factor I / Q000187:drug effects / Q000378:metabolism / Q000627:therapeutic use*; D007335:Insulin-Like Growth Factor II / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D011986:Receptors, Somatotropin / Q000172:deficiency*; D013002:Somatomedins / Q000187:drug effects* / Q000378:metabolism; D013997:Time Factors
chemical_list: D002352:Carrier Proteins; D006131:Growth Inhibitors; D018969:Insulin-Like Growth Factor Binding Proteins; D011986:Receptors, Somatotropin; D013002:Somatomedins; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D010450:Endopeptidases; C080473:insulin-like growth factor binding protein-3 protease