Opioid tonus and luteinizing hormone secretion in anorexia nervosa: priming effect with serotonin precursor L-5-hydroxytryptophan during pulsatile gonadotropin-releasing hormone administration.

In anorexia nervosa (AN) luteinizing hormone (LH) release is often impaired during opioid blockade. We investigated whether a restoration of the endogenous sex steroid milieu, together with a rise in central serotonergic tone, could increase LH responsiveness to Naloxone (NAL) in seven young women affected by AN. The spontaneous pulsatility of gonadotropins and their response to gonadotropin-releasing hormone (GnRH) and NAL challenges were tested before and after 13 days of pulsatile GnRH treatment and oral administration of L-5-hydroxytryptophan. Low and unpulsatile gonadotropin levels, responsive to GnRH, but not to NAL, were found before treatment. Pulsatile GnRH brought about a quasi-normal secretory pattern and 17 beta-estradiol increased to preovulatory levels in six of seven patients. On day 13 the lack of response to NAL administration was still present, however. A neuroendocrine disorder seems to be present in AN, which appears more complex than in other forms of hypothalamic amenorrhea.