Abnormal growth hormone responsiveness to stimuli in women with active celiac sprue

Baseline somatomedin C (Sm-C) and responses of growth hormone (GH), prolactin (PRL), and thyrotropin (TSH) to TSH-releasing hormone (TRH) and to L-dopa were evaluated in 10 untreated and nine treated women with celiac sprue, and in 10 normal women. Mean basal Sm-C, GH, PRL, and TSH levels were similar in all groups of subjects. In all subjects, L-dopa decreased PRL levels, without affecting TSH, and TRH increased PRL and TSH levels. In both controls and treated patients, TRH did not influence GH secretion, whereas L-dopa significantly increased GH levels. In untreated patients, GH levels paradoxically increased after TRH (8/10) but were unaffected by L-dopa (7/10). Because L-dopa would stimulate hypothalamic GH-releasing hormone (GHRH) secretion, four untreated patients, unresponsive to L-dopa, received GHRH, and GH levels rose markedly. These data suggest that, in untreated celiac sprue patients, hypothalamic control of GH secretion is reversibly impaired.