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 growth hormone releasing hormone (GHRH) 1-29 (30 microg/kg) for 6 months were studied in 16 slowly growing prepubertal children with idiopathic short stature (ISS; Group 1) and 8 similar children with growth hormone neurosecretory dysfunction (GHND; Group 2). Each child underwent endogenous growth hormone evaluation using both pharmacological and physiological testing; each had stimulated values > 10 microg/l and were subsequently placed into one of two groups based on pooled 12-hour overnight GH of < or > or = 3 microg/l. Each patient was followed every three months for one year. There were no significant differences in the two groups throughout the study with the exception of the endogenous GH levels. Both groups responded to GHRH therapy with similar significant increases in their rates of growth. Although a subset of patients (6 of 21) continued to grow at a rate significantly greater than the pre-therapy rate of growth, overall rates of growth were not significantly different from the pre-therapy growth rates 6 months following the discontinuation of GHRH treatment. We conclude that GHRH 1-29, given in the doses provided, leads to similar changes in growth rates in short, slowly growing children who are GH sufficient and those with GHND. Despite prior reports to the contrary, GHND patients do not experience a sustained increased in growth rate upon discontinuation of GHRH.