Growth during and after a trial of growth hormone releasing hormone 1-29 in children with idiopathic short stature or growth hormone neurosecretory dysfunction

The growth promoting effects of once nightly subcutaneous injections of gro wth hormone releasing hormone (GHRH) 1-29 (30 mu g/kg) for 6 months were st udied in 16 slowly growing prepubertal children with idiopathic short statu re (ISS; Group 1) acid 8 similar children with growth hormone neurosecretor y dysfunction (GHND; Group 2). Each child underwent endogenous growth hormo ne evaluation using both pharmacological and physiological testing; each ha d stimulated values > 10 mu g/l and were subsequently placed into one of tw o groups based on pooled 12-hour overnight GH of < or 2 3 mu g/l. Each pati ent was followed every three months for one year. There were no significant differences in the two groups throughout the study with the exception of t he endogenous GH levels. Both groups responded to GHRH therapy with similar significant increases in their rates of growth. Although a subset of patie nts (6 of 21) continued to grow at a rate significantly greater than the pr e-therapy rate of growth, overall rates of growth were not significantly di fferent from the pre-therapy growth rates 6 months following the discontinu ation of GHRH treatment. We conclude that GHRH 1-29, given in the doses pro vided, leads to similar changes in growth rates in short, slowly growing ch ildren who are GH sufficient and those with GHND. Despite prior reports to the contrary, GHND patients do not experience a sustained increased in grow th rate upon discontinuation of GHRH.