[Demonstration of the pulsatile secretion of LH-RH into hypophysial portal blood of ewes using an original technic for multiple samples].

Using a stereotaxic dorsal approach under lateral X-Ray control associated with a perfusion system, serial collections of hypophysial portal blood have been successfully obtained in three spayed ewes during 4 to 9 successive hrs. For the first time, pulsatile patterns of LH-RH secretion have been demonstrated in long term ovariectomized ewes. The frequency of LH-RH pulses recorded (about one pulse every 50 mn) agrees closely with the frequency of LH pulses in peripheral plasma of ovariectomized ewes. The technique allowed measurement of LH-RH in hypophysial portal blood thus providing a useful method for investigation of hypothalamo-pituitary gonadal interactions.