A comparative study of growth hormone (GH) and GH-releasing hormone(1-29)-NH2 for stimulation of growth in children with GH deficiency.

In this study, 60 patients with proven growth hormone deficiency (GHD) of hypothalamic origin were randomized into three equal groups, and received growth hormone-releasing hormone(1-29)-NH2 (GHRH(1-29)-NH2), 30 or 60 micrograms/kg/day, or growth hormone (GH), 0.1 IU/kg/day, for 6 months. There were no significant differences in growth between the two groups given GHRH(1-29)-NH2, but growth in the GH group was significantly better than in the other two groups (p < 0.01). Mean height velocities at 6 months were 9.2, 9.3 and 14.6 cm/year for the three groups, respectively. Plasma GHRH concentrations increased steadily over the 6-month treatment period, with higher levels in the group on the higher dose. During GHRH(1-29)-NH2 treatment, serum concentrations of insulin-like growth factor I rose initially, but then fell to values similar to those before treatment. No GH antibodies were detected, but all 20 patients on high-dose GHRH(1-29)-NH2 and 19 of 20 patients on low-dose GHRH(1-29)-NH2 developed GHRH antibodies. These had almost disappeared by 9 months after stopping treatment. There was no correlation between antibody titres and increase in height. No serious side-effects were seen, but three patients receiving GHRH(1-29)-NH2 reported mild irritation at the injection site. These results from the continuous infusion of GHRH(1-29)-NH2 over 6 months suggest that this treatment, or the related use of a depot preparation, is unlikely to be as effective as GH for the promotion of growth in GHD.