Growth hormone secretory dysfunction after hypothalamic and pituitary irradiation

Abstract

External cranial radiation is a major therapeutic tool in the treatment of various malignant diseases in children. As growth retardation has become a significant complication of this therapy, there have been quite a number of studies designed to elucidate its mechanism, especially its effects on hypothalamic and pituitary function. Ever since the earliest studies (Tan and Kunaratnam 1966; Larkins and Martin 1973; Samaan et al. 1975; Shalet et al. 1975; Perry-Keene et al. 1976; Richards et al. 1976; Czernichow et al. 1977) it has been very clear that growth hormone (GH) secretion is the most frequently altered function, with obvious consequences for growth. These studies demonstrated that the pituitary and hypothalamic injury was dose dependent, which explains why long-term consequences of cranial radiation differ according to the different therapeutic protocols used for each disease (Table 1).