[VIP removes the inhibition of prolactin secretion induced by dopamine in patients with prolactinoma].

PRL responsitivity after Vaso-active intestinal Peptide (VIP) infusion was studied during a Dopamine (DA) infusion, in normal women and women with a prolactinoma. VIP alone (6.2 micrograms/min., 12 min.) increases PRL in normal females, but does not remove DA-induced PRL-decrease (1 microgram X kg X X min.-1). It has no effect in women with prolactinoma. In these women, PRL increases when VIP is administered at the 200th minute of DA infusion (1 microgram X kg/min.). A PRL release by VIP in women with a prolactinoma, could imply the restitution of a DA inhibitory control. The same dose of VIP does not modify PRL, when administered during a 4 microgram X kg/min. infusion of DA, in women with a prolactinoma.