STIMULATION OF PROLACTIN-RELEASE BY NEUROKININ-A IN-VITRO

Since recent reports suggest that neurokinin A (NKA) may be involved i n the control of prolactin secretion, we studied tile effect of NKA on in vitro prolactin release. NKA (10(-7) M) stimulated prolactin secre tion from hemipituitaries of intact male rats. In addition, an anti-NK A serum (ANKA) inhibited basal and NKA-induced prolactin release. Nord ihydroguaiaretic acid inhibited the stimulatory effect of NKA on PRL s ecretion. Neither NKA nor ANKA have significant effects on in vitro PR L release from hemipituitaries of ovariectomized female rats. These re sults show that, in male rats, NKA may play an intrapituitary role in the maintenance of basal prolactin secretion as paracrine/autocrine st imulatory factor.