Clinical applications of LHRH and its analogues.

The physiological requirement for activation of pituitary gonadotrophin secretion by pulsatile LHRH stimulation is discussed, and compared with the effect of pituitary stimulation by LHRH agonists. Initial stimulation is followed by a phase of progressive pituitary and gonadal inhibition. This inhibition is fully reversible at the end of agonist treatment. Clinical applications of high dose suppression are the treatment of precocious puberty and hormone-dependent tumours (mammary and prostatic carcinoma). In women, agonist administration by nasal spray is a reversible method of inhibiting ovulation, and may also be useful in the treatment of endometriosis. Clinical advantages of agonist therapy are favourable biological tolerance, lack of side effects and rapid reversibility.