Abstract
Hexarelin (Hex) is a synthetic hexapeptide with potent GH-releasing activity in both animals and men. Aim of this study was to evaluate the GH response to a maximal dose of Hex and GH-releasing hormone (GHRH) in a group of patients with Prader-Willi syndrome (PWS). Seven patients (4 boys and 3 girls, age 2.4–14.2 yr) with PWS, 10 prepubertal obese children (7 boys and 3 girls, age 7.5–12.0 yr), and 24 prepubertal short normal children (11 boys and 13 girls, age 5.9–13 yr) with body weight within ± 10% of their ideal weight were studied. All subjects were tested on two occasions with GHRH 1–29 at the dose of 1 µg/Kg iv, and with Hex at the dose of 2 µg/Kg iv. In the PWS patients the GH response to GHRH (peak=6.4±2.0 µg/l, p<0.0001; AUC=248±70 µg min/l, p<0.0001) was significantly lower than that observed in the short normal children and similar to that observed in the obese children. In the PWS children the GH response to Hex (peak=7.5±1.6 µg/l; AUC=309±53) was similar to that observed after GHRH and significantly lower than that observed in the obese children (p<0.05). The results of this study show that PWS patients have a blunted GH response to the administration of a maximal dose of Hex. Whether these findings reflect a more severe pituitary GH deficiency in PWS than in obese children or a deranged hypothalamic regulation of GH secretion need further investigation.
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Cappa, M., Raguso, G., Palmiotto, T. et al. The growth hormone response to hexarelin in patients with Prader-Willi syndrome. J Endocrinol Invest 21, 501–505 (1998). https://doi.org/10.1007/BF03347335
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DOI: https://doi.org/10.1007/BF03347335