Identification of inhibitory and stimulatory control of prolactin secretion in the rhesus monkey.

In the unanesthetized, ovariectomized rhesus monkey, gonadotropin secretion is episodic while prolactin (Prl) release is relatively constant. Under pentobarbital anesthesia, however, Prl secretion also becomes pulsatile in synchrony with the discharges of LH. This finding suggests that the anesthesia has unmasked normally inhibited Prl releasing stimuli which are driven by the circhoral 'clock' that also times the discharges of GnRH.