Abstract
Abnormalities of GH secretion have previously been reported in children given cranial irradiation for CNS prophylaxis in acute lymphocytic leukemia or for brain tumors. To better define these neuroendocrine abnormalities, prospective longitudinal studies of GH secretion were performed in young adult male rhesus monkeys (N=4 in each group). Two doses of cranial irradiation were given (2400 or 4000 rad in 10 fractions over 2 weeks). Three consecutive provocative tests of GH secretion were used (arginine infusion, insulin induced hypoglycemia and L-Dopa stimulation) prior to radiation and 10, 30 and 50 weeks after radiation. The 2400 rad group at 10 weeks had an excessive and prolonged GH response to arginine (GH at 30, 60 and 90 min was 15±15, 37±11 and 30±11 ng/ml vs 22±4, 15±4 and 6±1 ng/ml for 13 controls, mean ± SE) and insulin (GH at 30 and 60 min was 46±13 and 49±7 ng/ml vs 40±9 and 8±1.5 ng/ml for 9 controls). In subsequent studies, GH responses to arginine and L-Dopa were normal, but GH response to insulin was blunted. In the 4000 rad group the arginine and L-Dopa tests were normal throughout, but the response to insulin was consistently blunted. In conclusion, there are abnormalities of GH secretion after cranial irradiation with doses frequently used in clinical practice, but their clinical significance is not yet clear. This may be a useful model for the study of neuroendocrine regulation of GH secretion.
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Bercu, B., Chrousos, G., Brown, T. et al. 385 ABNORMALITIES IN GROWTH HORMONE SECRETION AFTER CRANIAL IRRADIATION IN PRIMATES. Pediatr Res 15 (Suppl 4), 504 (1981). https://doi.org/10.1203/00006450-198104001-00396
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DOI: https://doi.org/10.1203/00006450-198104001-00396