Giving a short burst of growth‑hormone‑releasing hormone (like sermorelin) makes the pituitary release a normal amount of growth hormone even in women with anorexia who have very low estrogen, and the same is true when estrogen receptors are blocked with tamoxifen. Prolactin also rises a little right after the injection but then falls back to baseline.

Anorexia nervosa is associated with several abnormalities in GH secretion elicited by different stimuli. To investigate the precise mechanism of this alteration, GHRH was administered to 14 women: a group of eight anorexia nervosa patients in the acute phase of their illness and a control group of six age-matched volunteers. As patients with anorexia nervosa have chronic low oestrogen values, the volunteer women of the control group underwent a second GHRH test after pretreatment with the oestrogen receptor blocker tamoxifen. GHRH 1-29 (1 microgram/kg i.v.) induced a GH peak (mean +/- SEM) of 28.2 +/- 5.1 ng/ml (GH ng/ml x 2 = mU/l) at 30 min in the anorectic patients. This value was no different from the GHRH-stimulated GH peak in the control women (28.1 +/- 10.0 ng/ml). Tamoxifen pretreated women had a GH peak after GHRH of 35.6 +/- 9.7 ng/ml, not significant versus control test. Compared with the control group, oestrogen levels were significantly lower in anorectic patients and higher in tamoxifen-treated women. GHRH administration induced a small PRL peak at 15 min that was similar in the three groups tested. After this 15 min peak, PRL in both anorexic and tamoxifen-treated women returned toward basal values steadily. However, in untreated control women a second PRL peak was evident at 60 min. In conclusion, GHRH-induced GH secretion in anorexia nervosa patients was similar to that in control subjects and in controls under oestrogen receptor blockade.