GHRP-2 belongs to a family of peptides derived from enkephalin which stimulate growth hormone release Their mechanism of action is not clear, but there is evidence that they may act at hypothaiamic and/or pituitary sites. We have previously shown that GHRP's acutely stimulate growth hormone secretion in 60% of GH deficient children. With lower molecular with lower molecular weight and longer half life than GH and GHRH. they may represent an option for the therapy of GHD children. In the present study we studied the effect of prolonged GHRP-2 administration to these children. Six prepubertal GHD children (4M.2F) were treated with GHRP and GHRH for 8 months. GHD was detined as patients with a growth velocity <4 cm/year, significantly delaved bone age, and maximum GH response to 2 provocative test below 4 ng/ml. Chronological ages were between 10 9/12 ± 2 10/12 and bone ages 7 9/12± 2 1/12 (mean±SD). The patients received GHRP-2 sc at increasing doses every 2 months: 0.3,1 and 3 ug/K/day. During the last 2 months they received 3 ug/K/day of GHRP-2 and GHRH combined. Patients were admitted at 0,2,4,6, and 8 months for a baseline blood sample (CBC. blood chemistry, unnalysis, T3, T4, TSH, cortisol, EGF-1 and IGFBP-3) and blood sampling every 20 minutes during 12 hours for GH measurements (6PM-6AM). Results are shown in the table (mean ± SD)*=<p0.05 by ANOVA.

Table 1
Full size table

Conclusions: We observed a significant increase in growth velocity compared to baseline with 3 ug K/day of GHRP and when both peptides were administered together. Maximum concentrations and the pulse amplitude of GH increased significantly at the higher dose. We did not observe any clinical or biochemical adverse effects during the course of the study We conclude that that GHRP-2 may be useful for the therapy of GHD children.