title: Ontogeny of prolactin receptors in rat decidual tissue: binding by a locally produced prolactin-like hormone.
abstract: The objectives of this investigation were to determine whether decidual tissue possesses specific binding sites for prolactin, and to examine whether the locally produced prolactin-like hormone binds to these receptors. Characterization of the binding of prolactin to decidual tissue from rats at day 9 of pseudopregnancy revealed specific, high-affinity sites. Binding approached saturation with increasing concentrations of either the ligand or the protein. Cytosolic extracts of day-9 decidual tissue, containing various amounts of decidual luteotrophin which possesses several of the physiological and biochemical characteristics of prolactin, displaced the binding of 125I-labelled prolactin to decidual membranes in a linear fashion. Prolactin-binding sites were detectable 72 h after induction of decidualization and 48 h after the appearance of decidual luteotrophin in the decidua. Prolactin receptor concentrations increased significantly between days 8 and 9, reached a plateau between days 9 and 12 and declined abruptly on days 14 and 15, accompanied by a similar decline in decidual luteotrophin concentration in the tissue. Thus rat decidual tissue possesses specific receptors for prolactin to which decidual luteotrophin locally produced can bind, thereby suggesting an auto/paracrine role for this substance.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D003656:Decidua / Q000378:metabolism*; D005260:Female; D010908:Pituitary Hormones, Anterior / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism*; D011485:Protein Binding; D011555:Pseudopregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D011956:Receptors, Cell Surface / Q000032:analysis* / Q000378:metabolism; D011981:Receptors, Prolactin
chemical_list: D010908:Pituitary Hormones, Anterior; D011956:Receptors, Cell Surface; D011981:Receptors, Prolactin; C045090:luteotropin, decidual; D011388:Prolactin