Properties of a prolactin receptor from the rabbit mammary gland.
Receptors for human, simian, ovine, bovine and murine prolactin, human growth hormone and human placental lactogen have been identified in plasma-membrane-containing subcellular particles isolated from rabbit mammary glands. The association and dissociation of (125)I-labelled prolactin are time- and temperature-dependent processes, both being maximal at 37 degrees C. (125)I-labelled prolactin prepared by the enzymic iodination procedure with lactoperoxidase binds better to receptors than does the preparation obtained by using chloramine-t as the oxidizing agent. The binding of (125)I-labelled prolactin to receptors is strongly influenced by pH and ionic composition but not by many low-molecular-weight compounds tested, e.g. steroids, nucleotides and several drugs. Receptor activity is sensitive to trypsin and phospholipase C digestion, suggesting that protein and phospholipid moieties are essential for the binding of (125)I-labelled prolactin. The binding of (125)I-labelled prolactin to receptors is a saturable and reversible process. Scatchard and Lineweaver-Burk analyses suggest that (125)I-labelled prolactin has a high affinity for its receptor. Binding of (125)I-labelled prolactin to receptors does not result in the destruction of the hormone. Considerable prolactin-binding activity is also observed in subcellular fractions isolated from the adrenal gland, liver, ovary and kidney of the pregnant rabbit, a finding that is consistent with other reported actions of prolactin in these organs.
D000311:Adrenal Glands / Q000032:analysis; D000818:Animals; D002417:Cattle; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D000882:Haplorhini; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007457:Iodine Radioisotopes; D007668:Kidney / Q000032:analysis; D007700:Kinetics; D008099:Liver / Q000032:analysis; D008321:Mammary Glands, Animal / Q000378:metabolism*; D051379:Mice; D010053:Ovary / Q000032:analysis; D010740:Phospholipases; D011247:Pregnancy; D011388:Prolactin / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D011956:Receptors, Cell Surface; D012756:Sheep; D013347:Subcellular Fractions / Q000032:analysis; D013696:Temperature; D013997:Time Factors; D014357:Trypsin
D007457:Iodine Radioisotopes; D011956:Receptors, Cell Surface; D011388:Prolactin; D013006:Growth Hormone; D010740:Phospholipases; D014357:Trypsin