title: Factors influencing the growth hormone peak and plasma insulin-like growth factor I in young adults with pituitary stalk interruption syndrome.
abstract: BACKGROUND
  The diagnostic criteria for growth hormone (GH) deficiency (GHD) in adolescents and young adults are not yet clearly established.We evaluated the factors influencing the GH peak and plasma insulin-like growth factor (IGF) I in order to determine the cut-off limits for the diagnosis of GHD during the transition period.
  
  
  METHODS
  21 patients treated for GHD due to pituitary stalk interruption syndrome at 5.7 +/- 4.1 years were reevaluated at 16.0 +/- 1.8 years, 0.6 +/- 0.6 years after the end of GH treatment. Group 1 had isolated GHD (n = 9) and group 2 had multiple pituitary deficiencies (n = 12), including deficiencies of thyroid stimulating (n = 12), adrenocorticotropin (n = 8) and gonadotropin (n = 9) hormones.
  
  
  RESULTS
  At diagnosis, group 1 had a greater pituitary height (2.8 +/- 1.2 vs 1.6 +/- 1.1 mm, P = 0.03) and GH peak (3.8 +/- 1.9 vs 1.6 +/- 1.5 ng/ml, P < 0.02) than did group 2.At last evaluation, group 1 had greater GH peak (3.9 +/- 1.9 vs 0.2 +/- 0.4 ng/ml, P = 0.0001) and plasma IGF I (211 +/- 88 vs 78 +/- 69 ng/ml, P < 0.002) than did group 2. No group 1 and 9 group 2 patients had an undetectable GH peak, while the 3 others had GH peak below 1 ng/ml.The GH peak decreased between diagnosis and last evaluation only in group 2 (P < 0.008).
  
  
  CONCLUSIONS
  The GH peak response to pharmacological stimulation and the plasma IGF I concentration in young adults with GHD of childhood onset depend on the presence of additional pituitary deficiencies, reflecting a more severe defect of the hypothalamic-pituitary axis. The sex steroids cannot increase the IGF I if the GH secretion is zero.
authors.affiliation: Université Paris Descartes and Assistance Publique Hôpitaux de Paris, Hôpital Bicêtre, Unité d'Endocrinologie Pédiatrique, 94270 Le Kremlin Bicêtre, France. marimarcu@yahoo.com
authors.forename: Mariana
authors.initials: M
authors.lastname: Marcu
authors.forename: Christine
authors.initials: C
authors.lastname: Trivin
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Souberbielle
authors.forename: Raja
authors.initials: R
authors.lastname: Brauner