Treatment effects of GHRP-2 in children with short stature.
Pihoker C; Badger TM; Reynolds GA; Bowers CY
Department of Pediatrics, University of
Washington, Seattle 98105,
USA.
J Endocrinol, 1997 Oct, 155:1, 79-86
Abstract
Growth hormone-releasing peptide (GHRP)-2 is a
synthetic six amino acid peptide that is a
potent GH secretagogue. Although it shares no
structural homology with GH-releasing
hormone, in clinical studies its actions on the
pituitary release of GH are similar. It is effective
when administered orally and intranasally. For
children with GH deficiency, such noninvasive
treatments are most desirable and in need of
development. Fifteen children with short stature
participated in this study. All of the children had a height < 2 S.D. below mean for age, poor
height velocity, delayed bone age, and low
serum concentrations of IGF-1. These children
had been tested with standard GH secretagogues,
e.g. arginine,insulin, and L-dopa. Fifty
percent of the children were GH deficient, the
remainder had idiopathic short stature. The
children received testing with GHRH and GHRP-2
as an acute i.v.bolus of 1 microgram/kg;
all children in this study demonstrated a GH
response > 20micrograms/l. Each child in this
study also demonstrated a GH response > 10micrograms/l in response to intranasal GHRP-2, in the dose range of ¡°5-20 micrograms/kg¡±. The children were administered intranasal GHRP-2, 5-15 micrograms/kg, twice a day for 3 months,then three times a day. Fifteen children
participated in the study for 6 months; six of the children have participated for 18-24 months. Height velocity, serum IGF-1,IGF-binding protein 3(IGFBP-3)and GH-binding protein (GHBP) concentrations, and GH responses to GHRP-2 by i.v. bolus and intranasal spray were examined during treatment. Height velocity increased from 3.7 +/-0.2 cm/year to 6.1 +/- 0.3 cm/year at 6 months,6.0 +/- 0.4 cm/year at 18-24 months.There were no significant changes in IGF-1 or IGF-PB3 concentrations, or in acute GH responses to i.v. or intranasal GHRP-2. GHBP concentrations rose significantly, from 439+/- 63 pmol/l to 688 +/- 48 pmol/l. In this study GHRP-2 administration was well tolerated, and produced a modest but significant increase in growth velocity.