[Pulsatile GnRH substitution in Kallmann's syndrome in women]

Anosmia and primary amenorrhoea are guiding symptoms of Kallmann's syndrome (olfacto-genital syndrome) in which agenesis of the olfactory lobe is associated with congenital defects in the mediobasal region of the hypothalamus, thus preventing a sufficient GnRH synthesis. In three patients with Kallmann's syndrome, the secretion of gonadotropins on bolus injection of 25 micrograms GnRH was comparable with prepubertal reaction. In one patient, the hypophyseal function was normalized, and ovulatory cycles were induced by pulsatile GnRH substitution via a portable computerized pump (Zyklomat). Pregnancy occurred. The duration of treatment required to induce ovulation was identical during two subsequent treatment cycles, contrary to observations in functional hypothalamic amenorrhoeas. The marked ovarian reaction shows that even if there is no endogenous GnRH secretion, a pulsatile dose of less than 20 micrograms seems to be sufficient.