SHORT-TERM PITUITARY DESENSITIZATION - EFFECTS OF DIFFERENT DOSES OF THE GONADOTROPIN-RELEASING-HORMONE AGONIST TRIPTORELIN

Gonadotrophin-releasing hormone agonists (GnRHa) are used to prevent i nadequate luteinizing hormone (LH) surges during ovarian stimulation i n in-vitro fertilization (IVF), Dose studies for optimal dose assessme nt are lacking and unfavourable effects of the agonist on granulosa fu nction and oocyte quality have been suggested. This double-blind rando mized study was undertaken to assess the effect of four different dose s of triptorelin on the degree of desensitization of the pituitary, an d the recovery time of pituitary function after withdrawal of the agon ist, Sixty-six regularly cycling women were allocated to a treatment g roup (n = 32) and a control group (n = 34). To assess the degree of pi tuitary desensitization and restoration in the treatment group, gonado trophin releasing hormone (GnRH) challenges (100 mu g, i.v.) were perf ormed during treatment (day 17), and 2, 4 and 6 days after discontinua tion of treatment, At the same time blood samples for oestradiol and t riptorelin concentrations were drawn, In the control group a GnRH test was performed on day 2 of the menstrual cycle, Both pituitary desensi tization during and pituitary recovery after agonist treatment, expres sed as the LH response to exogenous GnRH, appeared to be dose dependen t, As the use of reduced dosages still offers a considerable degree of pituitary suppression, studies on dose adjustments in the use of trip torelin in ovarian stimulation in IVF are warranted.