Pituitary size assessed with magnetic resonance imaging as a measure of growth hormone secretion in long term survivors of childhood cancer

J Clin Endocrinol Metab. 1994 Oct;79(4):1122-7. doi: 10.1210/jcem.79.4.7525626.

Abstract

We investigated 37 long term survivors of childhood cancer to study the relationship among growth, GH secretion, and pituitary size. The median follow-up time after diagnosis was 13.2 yr. The pituitary gland was visualized with magnetic resonance imaging. Radiated patients (n = 25) had a reduced relative height and showed a greater reduction in relative height after diagnosis than nonradiated patients (n = 12). The patients had lower spontaneous nocturnal GH secretion than controls due to a reduced peak amplitude. Spontaneous GH secretion was lower in radiated patients than in nonradiated subjects. The patients had lower plasma insulin-like growth factor-I (IGF-I) and serum IGF-binding protein-3 (IGFBP-3) concentrations than the controls. Radiated subjects had decreased IGF-I and IGFBP-3 concentrations compared to nonradiated subjects. Half of the patients (20 of 37) evaluated with magnetic resonance imaging had a reduced pituitary size (pituitary height, < -2 SD score). Radiated subjects had smaller pituitary glands than nonradiated ones. Seventeen of 20 patients (85%) with reduced pituitary size had decreased nocturnal GH release. There was a positive correlation between nocturnal GH secretion, plasma IGF-I, and serum IGFBP-3 levels, on the one hand, and pituitary height, on the other. These results indicate that cranial radiation may result in tissue damage, leading to decreased pituitary size, reduced spontaneous GH secretion, and impaired linear growth. The finding of reduced IGF-I levels in both radiated and nonradiated patients combined with decreased IGFBP-3 concentrations in radiated patients, indicates that cytotoxic chemotherapy may induce hepatic damage resulting in decreased IGF-I synthesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Carrier Proteins / metabolism
  • Child
  • Cranial Irradiation
  • Female
  • Growth Hormone / metabolism*
  • Growth Hormone-Releasing Hormone
  • Humans
  • Insulin-Like Growth Factor Binding Proteins
  • Insulin-Like Growth Factor I / metabolism
  • Magnetic Resonance Imaging*
  • Male
  • Neoplasms / radiotherapy
  • Neoplasms / therapy*
  • Pituitary Gland / anatomy & histology*
  • Pituitary Gland / radiation effects
  • Somatomedins / metabolism
  • Survivors*

Substances

  • Carrier Proteins
  • Insulin-Like Growth Factor Binding Proteins
  • Somatomedins
  • Insulin-Like Growth Factor I
  • Growth Hormone
  • Growth Hormone-Releasing Hormone