Hyperprolactinemia-induced modifications in vasoactive intestinal peptide binding site densities in the rat central nervous system and pituitary gland: evidence for an interaction between estradiol-17 beta and prolactin effects.
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.
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INSERM U.55, Paris, France.
Vial
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Joubert-Bression
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Rostène
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D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D004343:Drug Implants; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006966:Hyperprolactinemia / Q000378:metabolism*; D010052:Ovariectomy; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011964:Receptors, Gastrointestinal Hormone / Q000187:drug effects / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide
D004343:Drug Implants; D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D004958:Estradiol