Growth hormone secretion and response to growth hormone therapy after treatment for brain tumour

Children irradiated for brain tumours constitute an increasing group of patients who will require GH therapy. High-dose cranial irradiation is necessary for cure, but inevitably causes GH deficiency within a few years. In 19 patients investigated between 2 and 9 years after irradiation, the spontaneous 24-hour GH secretion was markedly reduced. The secretory pattern indicated loss of regulating hypothalamic hormones. After exogenous GHRH was administered, the pituitary was able to respond with a prompt GH release, showing that pituitary function was unaffected. Ten prepubertal children growing at 3.8 +/- 0.3 cm/year were treated with GH, 0.1 IU/kg/day s.c. Their growth rate increased to 8.2 +/- 0.4 cm in the first year. An increased growth rate was also maintained in the second year.