[Pulsatile treatment with gonadotropin-releasing hormone (GnRH)]

The different ways of administration condition the frequency of the pulsatile GnRH, because of the different rate of depot. High frequencies (60-90/min) can be reached only with the intravenous route which is suitable for ovulation induction: ovulation is reached in 73-92% of women affected by hypothalamic amenorrhoea and in 41-51% of women affected by polycystic ovarian syndrome (previously suppressed with buserelin); overstimulation risk is lesser than during therapy with gonadotropins. Subcutaneous route is suitable for puberty induction which needs long-term treatment (18-24 months); the results are generally good, except in hypopituitaric patients. Intranasally route needs frequencies greater than 150-180 min: low frequencies administration (3 times/day) is sufficient to treat cryptorchidism and to reach good results (30-70%); moreover intranasally route can be useful to maintain the results reached with long term therapy with LHRH or gonadotropins.