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Growth hormone releasing hormone plus arginine stimulation testing in young adults treated in childhood with cranio-spinal radiation therapy.
Clin Endocrinol (Oxf). 2005 May; 62(5):628-32.CE

Abstract

OBJECTIVE

Growth hormone deficiency (GHD) secondary to cranio-spinal radiation therapy (CSRT) is a complication seen in medulloblastoma survivors. The standard for diagnosis of adult GHD is a peak GH < 3 microg/l by the insulin tolerance test (ITT). However, insulin tolerance testing exposes patients to the risks of hypoglycaemia. Recent studies suggest that the GH releasing hormone + arginine (GHRH + ARG) test can identify GHD in cranially irradiated patients at longer time intervals after radiation. We evaluated the GHRH + ARG stimulation test compared to the ITT in young adults diagnosed with medulloblastoma during childhood.

PATIENTS

We evaluated 10 young adult patients (age range 17-26 years) who were treated with CSRT during childhood for medulloblastoma, and who had resultant childhood-onset GHD.

MEASUREMENTS

Subjects underwent GH provocative testing with the ITT and the GHRH + ARG test. IGF-I and IGFBP3 levels were also measured at baseline.

RESULTS

Insulin tolerance testing and GHRH + arginine stimulation were performed at a mean +/- SD 14 +/- 4.4 years after cranial radiation. All patients failed the ITT with median peak GH 0.40 microg/l (range < 0.05-2.2). GHRH + arginine gave higher peak GH levels with a mean of 7.9 +/- 5.7 microg/l (P = 0.003). Four patients had peak GH > 9 microg/l and were between 7.8 and 19.6 years from cranial radiation. There was no correlation of peak GH levels with time interval since CSRT. Thirty-three per cent of subjects had normal IGF-I; neither IGF-I nor IGFBP3 standard deviation scores (SDS) correlated with ITT results.

CONCLUSIONS

Using a GHRH + arginine cut-off for GHD of 9 microg/l, four patients would have been misclassified as GH sufficient, despite being > 7 years (with two patients being nearly 20 years) out from CSRT. These findings suggest that the pituitary GH-producing cells of young adults continue to maintain responsiveness to GHRH + arginine more than 5-10 years after cranial irradiation.

Authors+Show Affiliations

Division of Endocrinology and Diabetes, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Evaluation Study
Journal Article
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

15853837

Citation

Ham, J Nina, et al. "Growth Hormone Releasing Hormone Plus Arginine Stimulation Testing in Young Adults Treated in Childhood With Cranio-spinal Radiation Therapy." Clinical Endocrinology, vol. 62, no. 5, 2005, pp. 628-32.
Ham JN, Ginsberg JP, Hendell CD, et al. Growth hormone releasing hormone plus arginine stimulation testing in young adults treated in childhood with cranio-spinal radiation therapy. Clin Endocrinol (Oxf). 2005;62(5):628-32.
Ham, J. N., Ginsberg, J. P., Hendell, C. D., & Moshang, T. (2005). Growth hormone releasing hormone plus arginine stimulation testing in young adults treated in childhood with cranio-spinal radiation therapy. Clinical Endocrinology, 62(5), 628-32.
Ham JN, et al. Growth Hormone Releasing Hormone Plus Arginine Stimulation Testing in Young Adults Treated in Childhood With Cranio-spinal Radiation Therapy. Clin Endocrinol (Oxf). 2005;62(5):628-32. PubMed PMID: 15853837.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Growth hormone releasing hormone plus arginine stimulation testing in young adults treated in childhood with cranio-spinal radiation therapy. AU - Ham,J Nina, AU - Ginsberg,Jill P, AU - Hendell,Christine D, AU - Moshang,Thomas,Jr PY - 2005/4/28/pubmed PY - 2005/7/15/medline PY - 2005/4/28/entrez SP - 628 EP - 32 JF - Clinical endocrinology JO - Clin. Endocrinol. (Oxf) VL - 62 IS - 5 N2 - OBJECTIVE: Growth hormone deficiency (GHD) secondary to cranio-spinal radiation therapy (CSRT) is a complication seen in medulloblastoma survivors. The standard for diagnosis of adult GHD is a peak GH < 3 microg/l by the insulin tolerance test (ITT). However, insulin tolerance testing exposes patients to the risks of hypoglycaemia. Recent studies suggest that the GH releasing hormone + arginine (GHRH + ARG) test can identify GHD in cranially irradiated patients at longer time intervals after radiation. We evaluated the GHRH + ARG stimulation test compared to the ITT in young adults diagnosed with medulloblastoma during childhood. PATIENTS: We evaluated 10 young adult patients (age range 17-26 years) who were treated with CSRT during childhood for medulloblastoma, and who had resultant childhood-onset GHD. MEASUREMENTS: Subjects underwent GH provocative testing with the ITT and the GHRH + ARG test. IGF-I and IGFBP3 levels were also measured at baseline. RESULTS: Insulin tolerance testing and GHRH + arginine stimulation were performed at a mean +/- SD 14 +/- 4.4 years after cranial radiation. All patients failed the ITT with median peak GH 0.40 microg/l (range < 0.05-2.2). GHRH + arginine gave higher peak GH levels with a mean of 7.9 +/- 5.7 microg/l (P = 0.003). Four patients had peak GH > 9 microg/l and were between 7.8 and 19.6 years from cranial radiation. There was no correlation of peak GH levels with time interval since CSRT. Thirty-three per cent of subjects had normal IGF-I; neither IGF-I nor IGFBP3 standard deviation scores (SDS) correlated with ITT results. CONCLUSIONS: Using a GHRH + arginine cut-off for GHD of 9 microg/l, four patients would have been misclassified as GH sufficient, despite being > 7 years (with two patients being nearly 20 years) out from CSRT. These findings suggest that the pituitary GH-producing cells of young adults continue to maintain responsiveness to GHRH + arginine more than 5-10 years after cranial irradiation. SN - 0300-0664 UR - https://www.unboundmedicine.com/medline/citation/15853837/Growth_hormone_releasing_hormone_plus_arginine_stimulation_testing_in_young_adults_treated_in_childhood_with_cranio_spinal_radiation_therapy_ L2 - https://doi.org/10.1111/j.1365-2265.2005.02272.x DB - PRIME DP - Unbound Medicine ER -