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Growth hormone responses to growth hormone-releasing hormone in Hand-Schüller-Christian Disease
M C Gelato1, D L Loriaux, G R Merriam
1Developmental Endocrinology Branch, NICHHD, Bethesda, Md.
Insights
Growth hormone-releasing hormone (GHRH) stimulated growth hormone (GH) release in patients with growth hormone deficiency (GHD). Repeated GHRH doses enhanced GH response in both Hand-Schüller-Christian disease and idiopathic GHD groups.
Area of Science:
- Endocrinology
- Metabolism
Background:
- Growth hormone deficiency (GHD) affects adults and can stem from hypothalamic or idiopathic causes.
- Growth hormone-releasing hormone (GHRH) is a key regulator of growth hormone (GH) secretion.
Purpose of the Study:
- To investigate the GH response to acute and repeated GHRH administration in adult patients with GHD.
- To compare the efficacy of GHRH stimulation in patients with presumed hypothalamic GHD (Hand-Schüller-Christian disease) versus idiopathic GHD.
Main Methods:
- Two groups of adult GHD patients (Hand-Schüller-Christian disease and idiopathic GHD) received intravenous bolus doses of GHRH.
- GH and insulin-like growth factor-I (IGF-I) levels were measured following acute and 5-day daily GHRH administration.
Main Results:
- Patients with Hand-Schüller-Christian disease showed a significantly higher GH response to the initial GHRH dose compared to those with idiopathic GHD.
- Both groups exhibited significantly enhanced GH responses after 5 days of daily GHRH stimulation, with a greater increase observed in the Hand-Schüller-Christian disease group.
- GH responses in GHD patients were lower than those observed in healthy adults.
Conclusions:
- GHRH effectively stimulates GH release in adult GHD patients, irrespective of etiology.
- Repeated GHRH administration leads to an augmented GH secretory capacity in GHD patients.
- The study suggests potential differences in GHRH responsiveness between hypothalamic and idiopathic GHD.
Abstract:
Bolus doses of GH-releasing hormone (GHRH), 1 microgram/kg i.v., were given to two groups of adult patients with growth hormone deficiency (GHD): 9 with Hand-Schüller-Christian disease (HSCD, presumed hypothalamic GHD) and 9 with idiopathic GHD (IGHD, etiology unknown). Six patients in each group were then given further GHRH doses daily for 5 days, and the GH responses to GHRH were measured over 3 h on day 1 and day 5. Plasma levels of insulin-like growth factor-I (IGF-I) were measured twice daily on days 1 and 5 during GHRH treatment. All patients with HSCD had measurable GH responses to the first dose of GHRH, with a mean peak response of 6.4 +/- 2.1 ng/ml (mean +/- SE). Only 5 of 9 patients with IGHD had GH responses above the detection limits of the assay; their mean peak response, 1.3 +/- 0.2 ng/ml, was significantly lower than the GH responses of the HSCD patients (p less than 0.05). Responses in both groups of patients were lower than those previously observed in normal adult men (35 +/- 8 ng/ml; p less than 0.01). Five days of daily stimulation with GHRH significantly (p less than 0.01) increased the GH response in both groups of patients. The rise was greater in patients with HSCD than with IGHD (HSCD, 5.1 +/- 2.5 ng/ml on day 1, vs. 12.0 +/- 6.8 ng/ml on day 5; IGHD, 1.4 +/- 0.3 ng/ml vs. 2.9 +/- 0.6 ng/ml).(ABSTRACT TRUNCATED AT 250 WORDS)