Differential dynamic responses of luteinizing hormone to gonadotropin releasing hormone in patients affected by bulimia nervosa-purging versus non-purging type.

Objective: Aim of the study was to investigate the presence of underlying abnormalities affecting the hypothalamus-pituitary-gonadal axis in 13 normal weight eumenhorreic bulimics as expressed by a different gonadotropin response to gonadotropin releasing hormone (GnRH), comparing patients with (n = 6) and without (n = 7) purging behaviours to controls (n = 5).

Method: Subjects were administered an intravenous GnRH infusion for four hours, with an additional bolus at first and third hour.

Results: Non-purging bulimics showed a significantly reduced luteinizing hormone (LH) response to GnRH compared to controls; purging bulimics, following the second bolus, demonstrated a statistically reduced peak, in comparison to both controls and non-purging bulimics.

Discussion: even in the absence of overt menstrual disturbances, an altered LH secretion elicited by pulsatile stimulation of endogenous GnRH was found, with a more severe impairment in purging than in non-purging bulimics, possibly related to their greater psychopathological and physical burden.