Effect of hexarelin on growth hormone secretion in Down syndrome

Letizia Ragusa, Antonino Alberti, Corrado Romano, Maria Rosa Valetto, Gianluca Aimaretti, Caterina Proto, Bruno P. Imbimbo, Romano Deghenghi, Fabio Colabucci, Ezio Ghigo

Research output: Contribution to journalArticlepeer-review


We studied the effect of the maximum response dose of hexarelin (HEX), a potent GH-releasing peptide (His-D,2,methyl,Trp-Ala-Trp-D,Phe-Lys-NH2) (HEX, 2 μg/kg i.v. at 0 min), comparing it with that of GHRH (2 μg/kg i.v. at 0 min) in 15 children with Down syndrome (DS, 10 M and 5 F, 7.5-15 years) and in 15 normal short children (NC, 9 M and 6 F, 8.2-15.5 years). Basal IGF-I levels were similar in DS and NC (313.85 ± 41.19 vs. 247.47 ± 38.63 μg/l). In DS, HEX induced a clear GH response (HEX vs. placebo, AUC 1,900.5 ± 301.7 vs. 116.1 ± 24.8 μg/l/h; p <0.0001) which was higher (p <0.05) than that after GHRH (1,051.0 ± 231.9 μg/l/h). The CH responses to HEX and to GHRH were similar in DS and in NC (AUC 1,936.0 ± 306.5 and 873.8 ± 190.3 μg/l/h). The effect of HEX was higher in pubertal than in prepubertal children (p <0.005). Thus, HEX releases more GH than GHRH also in DS, and the GH response to HEX as well as to GHRH is similar in DS and NC.

Original languageEnglish
Pages (from-to)204-210
Number of pages7
JournalDevelopmental Brain Dysfunction
Issue number4
Publication statusPublished - 1996


  • Down syndrome
  • Growth hormone
  • Growth hormone-releasing hormone
  • Hexarelin

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)


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