Growth hormone (GH) response to a single intravenous injection of synthetic GH-releasing hormone in prepubertal children with growth failure.

In this collaborative study involving 27 European medical centers, the plasma GH response to a single iv bolus dose of 2 micrograms/kg BW synthetic GHRH-(1-44)NH2 was determined in 574 children with growth failure of various etiologies. Analysis of the plasma GH response to GHRH was performed in 394 validated prepubertal children; these children were subdivided into 3 groups according to the degree of GH deficiency assessed within 6 months by conventional provocative tests (insulin, arginine, etc.): normal GH status (n = 210), partial GH deficiency (n = 73), or severe GH deficiency (n = 111). The mean peak GH values (+/- 2 SEM) after GHRH treatment in the three groups were 45.8 +/- 4.8, 29.2 +/- 6.3, and 16.8 +/- 3.1 microU/mL, respectively, and were greater than those after the conventional tests. The GH responses were consistent with the degree of GH deficiency based on the responses to the conventional tests. In addition, the areas under the GH response curves in the three groups were significantly different (P less than 0.0001). Among children with severe idiopathic GH deficiency 77% had a peak plasma GH level after GHRH above 10.0 microU/mL and 39% had a peak GH above 20.0 microU/mL. In these children, a single GHRH injection provides information on both their GH secretory capacity and the putative supresellar etiology of their GH deficiency, and may be of potential therapeutic value.