02 December 2008
Growth-hormone-releasing hormone (GHRH) tests were performed once [GHRH(1–29)NH<sub>2</sub>, 1 µg/kg] or on 2 consecutive days [GHRH(1–44)NH<sub>2</sub>, 1 and 2 µg/kg administered in random order] in 27 children with idiopathic, isolated growth hormone (GH)-deficiency and in 49 short normal children, all clinically prepubertal. No differences in GH release were found between the tests performed on the 1 st and 2nd day or according to GHRH dose or sex, both in GH-deficient and control children. 80% of GH-deficient and 87% of control children responded (GH peak > IO ng/ml) to GHRH(1–29)NH<sub>2</sub>, and 65% of GH-deficient and all control children to GHRH(1-44)NH<sub>2</sub>· No differences in GH release were found between GH-deficient GHRH responders and control children. 17% of GH-deficient and 10% of control children responded only to one of the two tests performed on 2 consecutive days; the lack of responsiveness was unrelated to GHRH dose and sequence of GHRH administration (1st or 2nd day). The GHRH test does not seem to be a reproducible test for the evaluation of GH release, nor is it useful to differentiate GH-deficient GHRH responders from short normal children.