The impact of irradiation on growth hormone responsiveness to provocative agents is stimulus dependent: results in 161 individuals with radiation damage to the somatotropic axis.

2.50
Hdl Handle:
http://hdl.handle.net/10541/84074
Title:
The impact of irradiation on growth hormone responsiveness to provocative agents is stimulus dependent: results in 161 individuals with radiation damage to the somatotropic axis.
Authors:
Lissett, Catherine A; Saleem, S; Rahim, Asad; Brennan, Bernadette M; Shalet, Stephen M
Abstract:
GH provocative tests remain the mainstay for the diagnosis of GH deficiency and at present the insulin tolerance test (ITT) is the gold standard. There are, however, a variety of other stimulation tests used in clinical practice. Each necessitates the use of a specific cut-off derived from normative data, but there remains a widely held view that the implications from a "failed" test are independent of the nature of the stimulus. We sought to examine whether this is the case in individuals with evidence of radiation damage to the somatotropic axis. One hundred and sixty-one nonacromegalic patients were identified who had undergone an arginine stimulation test (AST) and an ITT within a 3-month period as part of routine testing between 1975 and 1999. They were divided into those tested before (n = 81; 48 males) and those tested after (n = 80; 36 males) completion of growth and puberty. Patients were considered for inclusion in the study if they had a history of cranial irradiation and a GH response to one provocative test of less than 8 microg/L, taken as indicating that some damage to the GH axis may have occurred. The patients were compared with 2 control groups. The first comprised 35 adults (18 males) and the second consisted of 16 prepubertal children (10 males). The median peak (range) GH response to the ITT was significantly greater (P < 0.0001) than that to the AST in the adult controls: 24.9 (4.1--76.9) vs. 12.2 (0.88--35.0) microg/L, respectively. However, in the patients the GH responses were similar (P = 0.28): 2.2 (0.2--25.7) vs. 1.4 (0.2--12.8) microg/L to the ITT and AST, respectively. In contrast to the pattern seen in the adult controls, the response to an ITT in childhood controls was of similar magnitude (P = 0.5) to that to the AST: 17.5 (8.1--40.0) vs. 19.4 (7.3--53.8) microg/L, respectively. However in the patients, the GH response to the AST was greater than that to the ITT (P < 0.0001): 4.3 (0.7--17.2) vs. 3.0 (0.4--18.1) microg/L, respectively. In summary, we have shown that the impact of irradiation on GH responsiveness to provocative agents is stimulus dependent. The GH response to an AST appears to be more resistant to the effects of irradiation than that to the ITT. When investigating the impact of irradiation on GH secretory status, the GH response to an AST may be a less sensitive guide to the functional ability of the GH axis.
Affiliation:
Department of Endocrinology, Christie Hospital National Health Service Trust, Manchester, United Kingdom M20 4BX.
Citation:
The impact of irradiation on growth hormone responsiveness to provocative agents is stimulus dependent: results in 161 individuals with radiation damage to the somatotropic axis. 2001, 86 (2):663-8 J. Clin. Endocrinol. Metab.
Journal:
The Journal of Clinical Endocrinology and Metabolism
Issue Date:
Feb-2001
URI:
http://hdl.handle.net/10541/84074
PubMed ID:
11158028
Type:
Article
Language:
en
ISSN:
0021-972X
Appears in Collections:
All Christie Publications

Full metadata record

DC FieldValue Language
dc.contributor.authorLissett, Catherine Aen
dc.contributor.authorSaleem, Sen
dc.contributor.authorRahim, Asaden
dc.contributor.authorBrennan, Bernadette Men
dc.contributor.authorShalet, Stephen Men
dc.date.accessioned2009-10-12T15:38:42Z-
dc.date.available2009-10-12T15:38:42Z-
dc.date.issued2001-02-
dc.identifier.citationThe impact of irradiation on growth hormone responsiveness to provocative agents is stimulus dependent: results in 161 individuals with radiation damage to the somatotropic axis. 2001, 86 (2):663-8 J. Clin. Endocrinol. Metab.en
dc.identifier.issn0021-972X-
dc.identifier.pmid11158028-
dc.identifier.urihttp://hdl.handle.net/10541/84074-
dc.description.abstractGH provocative tests remain the mainstay for the diagnosis of GH deficiency and at present the insulin tolerance test (ITT) is the gold standard. There are, however, a variety of other stimulation tests used in clinical practice. Each necessitates the use of a specific cut-off derived from normative data, but there remains a widely held view that the implications from a "failed" test are independent of the nature of the stimulus. We sought to examine whether this is the case in individuals with evidence of radiation damage to the somatotropic axis. One hundred and sixty-one nonacromegalic patients were identified who had undergone an arginine stimulation test (AST) and an ITT within a 3-month period as part of routine testing between 1975 and 1999. They were divided into those tested before (n = 81; 48 males) and those tested after (n = 80; 36 males) completion of growth and puberty. Patients were considered for inclusion in the study if they had a history of cranial irradiation and a GH response to one provocative test of less than 8 microg/L, taken as indicating that some damage to the GH axis may have occurred. The patients were compared with 2 control groups. The first comprised 35 adults (18 males) and the second consisted of 16 prepubertal children (10 males). The median peak (range) GH response to the ITT was significantly greater (P < 0.0001) than that to the AST in the adult controls: 24.9 (4.1--76.9) vs. 12.2 (0.88--35.0) microg/L, respectively. However, in the patients the GH responses were similar (P = 0.28): 2.2 (0.2--25.7) vs. 1.4 (0.2--12.8) microg/L to the ITT and AST, respectively. In contrast to the pattern seen in the adult controls, the response to an ITT in childhood controls was of similar magnitude (P = 0.5) to that to the AST: 17.5 (8.1--40.0) vs. 19.4 (7.3--53.8) microg/L, respectively. However in the patients, the GH response to the AST was greater than that to the ITT (P < 0.0001): 4.3 (0.7--17.2) vs. 3.0 (0.4--18.1) microg/L, respectively. In summary, we have shown that the impact of irradiation on GH responsiveness to provocative agents is stimulus dependent. The GH response to an AST appears to be more resistant to the effects of irradiation than that to the ITT. When investigating the impact of irradiation on GH secretory status, the GH response to an AST may be a less sensitive guide to the functional ability of the GH axis.en
dc.language.isoenen
dc.subjectBrain Canceren
dc.subject.meshAdult-
dc.subject.meshAge Factors-
dc.subject.meshArginine-
dc.subject.meshBrain Neoplasms-
dc.subject.meshChild-
dc.subject.meshFemale-
dc.subject.meshHuman Growth Hormone-
dc.subject.meshHumans-
dc.subject.meshHypopituitarism-
dc.subject.meshInsulin-
dc.subject.meshMale-
dc.subject.meshPatient Selection-
dc.subject.meshPuberty-
dc.subject.meshRadioimmunoassay-
dc.subject.meshRadiotherapy-
dc.subject.meshReference Values-
dc.subject.meshReproducibility of Results-
dc.subject.meshSensitivity and Specificity-
dc.titleThe impact of irradiation on growth hormone responsiveness to provocative agents is stimulus dependent: results in 161 individuals with radiation damage to the somatotropic axis.en
dc.typeArticleen
dc.contributor.departmentDepartment of Endocrinology, Christie Hospital National Health Service Trust, Manchester, United Kingdom M20 4BX.en
dc.identifier.journalThe Journal of Clinical Endocrinology and Metabolismen

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