title: Progestin receptors in the ventromedial nucleus of the hypothalamus and arcuate nucleus-median eminence are decreased by idazoxan.
abstract: Steroid-dependent lordosis behavior in ovariectomized (OVX) guinea pigs is attenuated by alpha 1- and/or alpha 2-noradrenergic (NE) receptor antagonists. Correlated with the decrease in lordosis after alpha 1-NE receptor blockade by prazosin is a decrease in 'cytosol' progestin receptors in the ventromedial hypothalamic nucleus (VMN). We examined whether a presumed alpha 2-NE receptor blocker (idazoxan, IDA) also affects progestin receptors. A decrease in 'cytosol' progestin receptors was found after IDA treatment of OVX, estrogen-treated guinea pigs in the VMN and the arcuate nucleus-median eminence (ARC-ME). Apparently, either prazosin or IDA can inhibit lordosis behavior and decrease 'cytosol' progestin receptors in the VMN. In contrast, idazoxan but not prazosin, decrease 'cytosol' progestin receptors in the ARC-ME.
authors.affiliation: Institute of Animal Behavior, Rutgers University, Newark, NJ 07102.
authors.forename: P A
authors.initials: PA
authors.lastname: Vincent
authors.forename: H H
authors.initials: HH
authors.lastname: Feder
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004146:Dioxanes / Q000494:pharmacology*; D005260:Female; D006168:Guinea Pigs; D019329:Idazoxan; D008473:Median Eminence / Q000378:metabolism*; D009994:Osmolar Concentration; D011397:Promegestone / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism*; D014018:Tissue Distribution; D014697:Ventromedial Hypothalamic Nucleus / Q000378:metabolism*
chemical_list: D000317:Adrenergic alpha-Antagonists; D004146:Dioxanes; D011980:Receptors, Progesterone; D011397:Promegestone; D019329:Idazoxan