Plasma Growth Hormone Response to Synthetic GH-RH_1-4₄ in 52 Children and Adults with Growth Hormone Deficiency of Various Etiologies

Abstract

52 patients (42 children and 10 adults) with growth hormone deficiency (GHD), grouped into four diagnostic categories, and 6 children with constitutional short stature who served as controls were tested for plasma GH response to synthetic GH-RH_1–44 given in an intravenous bolus. The response was classified into three degrees according to the magnitude of the maximal rise: Good, > 9 ng/ml; Partial, 3.1–9.0 ng/ml; None, ≤ 3 ng/ml. Among the GHD patients the highest response was observed in patients with partial growth hormone deficiency (PGHD), and 60% of the children with isolated GH deficiency (IGHD) showed an increase in plasma GH levels. Nevertheless, the response of the GHD patients was lower than that in the control group. In the children and adolescents with PGHD and IGHD the response was not age related. Among those with multiple pituitary hormone deficiencies – idiopathic (MPHD-ID) there was no response in the adolescents although a hypothalamic disorder had been documented by other tests. Among those with MPHD – organic (MPHD-ORG) the GH-RH stimulated GH secretion in the patients with glioma, who had received only irradiation treatment, and in the youngest of the patients with craniopharyngioma. Of the 10 young adults tested none showed a good response. It is concluded that GH-RH is useful in differentiating between GH deficiency of hypothalamic origin and that of pituitary origin, and in selecting those patients who might benefit from long-term treatment with GH-RH in the future.

Responsiveness of pituitary hGH to GRH1-44 in juveniles with obesity

“…Synthetic GRHi_44 has been found to be useful in clinical practice for the evaluation of pituitary somatotroph function Rosen¬ thal et al 1983;Wood et al 1983;Pertzelan et al 1985). There is, however, only one report dealing with the response of hGH to GRH in obese individuals and in this series the subjects were adults with morbid obesity (Williams et al 1984).…”

“…Our investigation of 14 obese juveniles revealed two patterns of plasma hGH response to GRH. In the group with so-called simple obesity-the re¬ sponse of hGH to GRH was good (11.8 + 2.4 ng/ml) but less than in normal adolescents (49 ± 34; range 19-90 ng/ml) (Pertzelan et al 1985), whereas in the group suffering from syndromes associated with obesity it was very low (3.2 ± 1.4 ng/ml). Williams et al (1984) reported that the hGH response to GRH was related to the degree of obesity.…”

“…The lack of responsiveness of hGH to GRH in the patients suffering from syndromes associated with obesity can be considered to be evidence that in addition to the hypothalamic derangement there is also a pituitary impairment such as that described in patients with idiopathic multiple pituitary hormone deficiencies (Pertzelan et al 1985). …”

Factors Influencing the Growth Hormone Response to Growth Hormone-Releasing Hormone in Children with Idiopathic Growth Hormone Deficiency

“…It is difficult to compare reported data because the doses of GHRH administered have varied [3, 4], as have the limit of GH peak defining the low response, and the association of GHRH with other stimuli [1, 5]. The factors influencing the response are unclear.…”

Growth Hormone Release in Response to Growth Hormone-Releasing Hormone in Term and Preterm Neonates

“…Gestational age correlated positively with both basal and peak growth hormone concentra tions in our patients. In conclusion, first, neonates studied in their first days of life have high basal levels of growth hormone and fail to further secrete any significant amount of growth hormone following a single dose of GHRH, and, second, premature newborns secrete signif icantly less growth hormone than do term neonates.The availability of human pancreatic tu mor growth hormone-releasing hormones (hpGHRH-40 and hpGHRH-44), the latter of which is almost certainly identical to hy pothalamic GHRH, has allowed a number of investigators to study growth hormone re lease in normal adults [1][2][3], adolescents and older children [4,5] and in a diverse group of children with short stature [2][3][4][5].Adults and children undergoing pubertal changes differ in their response to GHRH; in adults it may be less brisk than in children [3] and the response may in fact decrease with advancing age [7], but there is a marked rise in GHRH levels during puberty [4,5],The growth hormone response to GHRH has to our knowledge only been evaluated in newborns in one previous study [6] and these …”