Journal of Clinical Endocrinology & Metabolism, Vol 64, 418-424, Copyright © 1987 by Endocrine Society

ARTICLES

Early effects of cranial irradiation on hypothalamic-pituitary function

KS Lam, VK Tse, C Wang, RT Yeung, JT Ma and JH Ho

Hypothalamic-pituitary function was studied in 31 patients before and after cranial irradiation for nasopharyngeal carcinoma. The estimated radiotherapy (RT) doses to the hypothalamus and pituitary were 3979 +/- 78 (+/- SD) and 6167 +/- 122 centiGrays, respectively. All patients had normal pituitary function before RT. One year after RT, there was a significant decrease in the integrated serum GH response to insulin- induced hypoglycemia. In the male patients, basal serum FSH significantly increased, while basal serum LH and testosterone did not change. Moreover, in response to LHRH, the integrated FSH response was increased while that of LH was decreased. Such discordant changes in FSH and LH may be explained by a defect in LHRH pulsatile release involving predominantly a decrease in pulse frequency. The peak serum TSH response to TRH became delayed in 28 patients, suggesting a defect in TRH release. Twenty-one patients were reassessed 2 yr after RT. Their mean basal serum T4 and plasma cortisol levels had significantly decreased. Hyperprolactinemia associated with oligomenorrhoea was found in 3 women. Further impairment in the secretion of GH, FSH, LH, TSH, and ACTH had occurred, and 4 patients had hypopituitarism. Thus, progressive impairment in hypothalamic-pituitary function occurs after cranial irradiation and can be demonstrated as early as 1 yr after RT.

This article has been cited by other articles:

				J. Bjork, K. Link, and E. M. Erfurth The Utility of the Growth Hormone (GH) Releasing Hormone-Arginine Test for Diagnosing GH Deficiency in Adults with Childhood Acute Lymphoblastic Leukemia Treated with Cranial Irradiation J. Clin. Endocrinol. Metab., November 1, 2005; 90(11): 6048 - 6054. [Abstract] [Full Text] [PDF]

				S. R. Peacey, A. A. Toogood, J. D. Veldhuis, M. O. Thorner, and S. M. Shalet The Relationship between 24-Hour Growth Hormone Secretion and Insulin-Like Growth Factor I in Patients with Successfully Treated Acromegaly: Impact of Surgery or Radiotherapy J. Clin. Endocrinol. Metab., January 1, 2001; 86(1): 259 - 266. [Abstract] [Full Text]

				S. R. Peacey, A. A. Toogood, and S. M. Shalet Hypothalamic Dysfunction in "Cured" Acromegaly Is Treatment Modality Dependent J. Clin. Endocrinol. Metab., May 1, 1998; 83(5): 1682 - 1686. [Abstract] [Full Text]

				M. L. Vance Hypopituitarism N. Engl. J. Med., June 9, 1994; 330(23): 1651 - 1662. [Full Text]