title: Growth hormone secretion in response to glucagon stimulation test in healthy middle-aged men.
abstract: OBJECTIVE
  To investigate the growth hormone (GH) response to glucagon stimulation test (GST) in a population of healthy men over 50 years old in comparison to insulin tolerance test (ITT), analysis of the spontaneous 24-hour GH profile and insulin-like growth factor 1 (IGF-I).
  
  
  METHODS
  27 healthy men aged between 51 and 65 years were tested.
  
  
  RESULTS
  Using non-parametric correlation analysis, a positive correlation between GH peak after GST and mean IGF-I (r = 0.528; p = 0.005) was found, as well with GH peak in 24-hour profile (r = 0.494; p = 0.009). No correlation was found comparing GH peak after ITT with the same parameters. Ten subjects presented GH peak of less than 3.0 microg/L after GST, none confirmed in ITT.
  
  
  CONCLUSIONS
  GH peak response to GST was lower than ITT, but it showed a positive correlation with mean IGF-I and also with GH peak in 24-hour profile. However, GST should not be used to differentiate organic growth hormone deficiency (GDH) from the expected decline on GH secretion due to aging.
authors: Departamento de Endocrinologia, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. dudamicmacher@ig.com.br
authors: Eduardo
authors: E
authors: Micmacher
authors: Roberto P
authors: RP
authors: Assumpção
authors: Renato G
authors: RG
authors: Redorat
authors: Luciana D
authors: LD
authors: Spina
authors: Ivan C
authors: IC
authors: Cruz
authors: Carla A
authors: CA
authors: Silva
authors: Mário
authors: M
authors: Vaisman
authors: Flávia Lúcia
authors: FL
authors: Conceição
mesh_terms: D000368:Aged; D005934:Glucagon; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D007328:Insulin; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric
chemical_list: D007328:Insulin; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; D005934:Glucagon