title: Growth hormone response to standard provocative stimuli and combined tests in very young children with Prader-Willi syndrome.
abstract: BACKGROUND
  In Prader-Willi syndrome (PWS) a reduced growth hormone (GH) response to several stimulators has been documented in many studies, but none have focused on very young children. We evaluated the pattern of GH secretion in very young PWS patients.
  
  
  METHODS
  Twenty-seven genetically confirmed PWS children (10 females, aged 0.4-5 years, mean: 2.2 ± 1.4 years) were included. All subjects underwent standard provocative tests (clonidine, CLO; and arginine, ARG) and one combined test [growth hormone-releasing hormone (GHRH) plus pyridostigmine (13 patients) or GHRH plus arginine (14 patients)]. Insulin-like growth factor-1 (IGF-1) levels were also measured.
  
  
  RESULTS
  While standard tests (CLO and ARG) showed low GH peak in 85.2 and 70.4% of the patients, respectively, the combined test was found to be normal in 85.2%. IGF-1 was low in 66.7% of patients. Out of 27 patients, 3 (11%) showed a normal GH peak with both standard tests (group A), 6 (22%) to one of the standard tests (group B) and 18 (67%) presented a low response to both standard tests (group C). Four subjects showed low response to both the combined and standard tests and reduced IGF-1.
  
  
  CONCLUSIONS
  Our data suggest that very young PWS children seem to have impaired hypothalamic GHRH secretion with a normal GH pituitary reserve.
authors: Autoimmune Endocrine Diseases Unit, Endocrinology Department, Bambino Gesù Children's Hospital, Research Institute, Palidoro (Rome), Italy.
authors: Girolamo
authors: G
authors: Di Giorgio
authors: Graziano
authors: G
authors: Grugni
authors: Danilo
authors: D
authors: Fintini
authors: Sarah
authors: S
authors: Bocchini
authors: Sabrina
authors: S
authors: Spera
authors: Marina
authors: M
authors: Cuttini
authors: Marco
authors: M
authors: Cappa
authors: Antonino
authors: A
authors: Crinò
mesh_terms: D058647:Adrenergic alpha-2 Receptor Agonists / Q000008:administration & dosage / Q000493:pharmacokinetics; D001120:Arginine / Q000008:administration & dosage / Q000493:pharmacokinetics; D002675:Child, Preschool; D002800:Cholinesterase Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics; D003000:Clonidine / Q000008:administration & dosage / Q000493:pharmacokinetics; D005260:Female; D013007:Growth Hormone-Releasing Hormone; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000493:pharmacokinetics; D006801:Humans; D007223:Infant; D008297:Male; D011218:Prader-Willi Syndrome / Q000097:blood* / Q000188:drug therapy; D011729:Pyridostigmine Bromide / Q000008:administration & dosage / Q000493:pharmacokinetics
chemical_list: D058647:Adrenergic alpha-2 Receptor Agonists; D002800:Cholinesterase Inhibitors; D019382:Human Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine; D011729:Pyridostigmine Bromide; D003000:Clonidine