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

@entity1 @entity851 @entity2301 @entity5 @entity442 @entity99
We investigated 37 long term survivors of childhood @entity5 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 @entity1 (n = 25) had a reduced relative height and showed a greater reduction in relative height after diagnosis than nonradiated @entity1 (n = 12). The @entity1 had lower spontaneous nocturnal GH secretion than controls due to a reduced peak amplitude. Spontaneous GH secretion was lower in radiated @entity1 than in nonradiated subjects. The @entity1 had lower plasma @entity442 ( @entity442 ) and serum @entity2301 ( @entity2301 ) concentrations than the controls. Radiated subjects had decreased @entity442 and @entity2301 concentrations compared to nonradiated subjects. Half of the @entity1 (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 @entity1 (85%) with reduced pituitary size had decreased nocturnal GH release. There was a positive correlation between nocturnal GH secretion, plasma @entity442 , and serum @entity2301 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 @entity851 . The finding of reduced @entity442 levels in both radiated and nonradiated @entity1 combined with decreased @entity2301 concentrations in radiated @entity1 , indicates that cytotoxic chemotherapy may induce @entity99 resulting in decreased @entity442 synthesis.
