title: Growth hormone receptor polymorphisms and growth hormone response to stimulation test: a pilot study.
abstract: BACKGROUND
  No gold standard pharmacological stimulation test exists for the diagnosis of growth hormone deficiency (GHD). In addition, the genetic factors that influence growth hormone (GH) responses remain unclear. This study aimed to determine whether polymorphisms in exon 6 of the GH receptor gene influence responses to the L-arginine GH stimulation test.
  
  
  METHODS
  This study included 27 prepubertal patients with confirmed GHD. GHD was defined as a peak GH level <8 ng/mL in response to pharmacological stimulation. The mean GH peak after L-arginine stimulation was 2.9±2.9 ng/mL.
  
  
  RESULTS
  The included patients had the following genotypes at the third position of codon 168: AA (N.=1), AG (N.=15) and GG (N.=11). Patients carrying the AA and AG genotypes exhibited stronger responses to arginine than patients with the GG genotype (3.1±2.7 vs. 1.5±1.3 ng/mL, P=0.01).
  
  
  CONCLUSIONS
  The approach employed in this study could elucidate GH profiles under physiological and pathological conditions, facilitating improved interpretation of pharmacological stimulation tests.
authors.affiliation: Unit of Pediatric and Adolescentology, Department of Internal Medicine and Therapeutics, Foundation IRCCS Polyclinic San Matteo, University of Pavia, Pavia, Italy.
authors.forename: Sara
authors.initials: S
authors.lastname: Pagani
authors.affiliation: Unit of Pediatric Endocrinology, Gaetano Rummo Hospital, Benevento, Italy.
authors.forename: Gianpaolo
authors.initials: G
authors.lastname: DE Filippo
authors.affiliation: Department of Health's Sciences, University of Eastern Piedmont, Novara, Italy.
authors.forename: Giulia
authors.initials: G
authors.lastname: Genoni
authors.affiliation: Department of Clinical Medicine and Surgery, Federico II University, Naples, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Rendina
authors.affiliation: Unit of Pediatric and Adolescentology, Department of Internal Medicine and Therapeutics, Foundation IRCCS Polyclinic San Matteo, University of Pavia, Pavia, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Meazza
authors.affiliation: Department of Pediatrics, Bambino Gesù Children Hospital, Rome, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Bozzola
authors.affiliation: Department of Health's Sciences, University of Eastern Piedmont, Novara, Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Bona
authors.affiliation: Unit of Pediatric and Adolescentology, Department of Internal Medicine and Therapeutics, Foundation IRCCS Polyclinic San Matteo, University of Pavia, Pavia, Italy - mauro.bozzola@unipv.it.
authors.forename: Mauro
authors.initials: M
authors.lastname: Bozzola
mesh_terms: D001120:Arginine / Q000494:pharmacology; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D019382:Human Growth Hormone; D006801:Humans; D010865:Pilot Projects; D011986:Receptors, Somatotropin / Q000235:genetics
chemical_list: D011986:Receptors, Somatotropin; D019382:Human Growth Hormone; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D001120:Arginine