Modifications induites par l’hyperprolactinémie dans les densités des sites de liaison des peptides intestinaux vasoactifs dans le système nerveux central du rat et l’hypophyse: mise en évidence d’une interaction entre les effets de l’estradiol-17 bêta et de la prolactine.
Hyperprolactinemia was induced in ovariectomized rats by implanting estradiol-17 beta pellets, grafting extrapituitaries, or by a combination of both treatments. Subsequently, the effect of increasing plasma prolactin levels on both central and pituitary receptors for vasoactive intestinal peptide (VIP), a neuropeptide known to stimulate prolactin release was investigated. The results obtained by quantitative autoradiography show that the density of VIP binding sites is modified in restricted areas of the central nervous system (striatum, several cortical, thalamic and limbic structures) and in the pituitary in hyperprolactinemic animals. The present results suggest that changes in plasma prolactin levels may control VIP receptor site density in both brain and pituitary. Moreover, direct effects of estradiol-17 beta and possible interactions between estradiol-17 beta and prolactin are observed on both brain and pituitary VIP binding sites.
Montagne MN, Vial M, Joubert-Bression D, Rostène W.