Growth hormone and prolactin response to growth hormone-releasing in anorexia nervosa

Anorexia nervosa (AN) is associated with several endocrine disorders. In order to investigate the role of these alterations, growth hormone-releasing hormone (GHRH) was administered in a group of 9 AN patients and in 9 healthy normal-weight women as control. Growth hormone (GH) and prolactin (PRL) levels were evaluated in both groups after GHRH and saline solution administration. In the AN group, luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyrotropin (TSH) and cortisol serum levels were evaluated during GHRH administration; somatomedin-C (Sm-C) basal levels were also determined. In both groups, GHRH induced a prompt GH increase, which was significantly higher in AN patients (55.3 +/- 2.9 ng/ml, mean +/- SE) than in normal subjects (9.8 +/- 2.6 ng/ml: p less than 0.01). A significant positive correlation between mean GH basal values and GH peak after GHRH was observed only in the control group (R = 0.82, p less than 0.01). No significant relationship between GH mean peak and body mass index (BMI) or Sm-C, estradiol (E2) and glucose serum levels was found in AN patients. However, a positive significant correlation with triiodothyronine (T3) basal values was observed in this group (R = 0.80, p less than 0.01). Both groups showed no variation in PRL serum levels after GHRH infusion. Our data suggest the presence of a central derangement in hypothalamic control of pituitary function in patients with AN, which is not necessarily due to weight loss alone.