Pituitary gland activity following ultralong versus long down regulation

ABSTRACT

The aim of this prospective comparative study was to investigate the pituitary gland activity after prolonged down regulation with Goserelin and after milder down regulation of patients underwent IVF treatment under long down regulation protocol with daily injections of Buscrelin. The pituitary activity of 21 patients received Goserelin [Zoladex] for 3 months was investigated and the results were compared with the pituitary activity of 50 patients received daily Buserelin from day 21 of the cycle preceding the IVF treatment cycle [8-14 days]. The pituitary gland achieved a profound degree of down regulation 4 weeks post Goserelin injections and maintained the same degree of down regulation following each subsequent injection. The LH and E2 were more profoundly suppressed by the depot GnRH agonist [Zoladex] than the daily Buserelin administration. However the pituitary remains responsive to Buserelin by producing pulses of FSH and LH despite the down regulation in both groups. The amplitude of these pulses were similar although the LH levels were significantly higher in group 2. These pulses are probably the source of endogenous LH required for steroidogenesis. This explains the success of IVF after profound down regulation despite the use of Pure FSH for ovarian stimulation