title: Modification of nuclear restriction in vitro by plasma from tumor-bearing animals.
abstract: Putative regulatory macromolecules, which may be useful in diagnosis or tumor detection, were identified in the peripheral blood plasma of tumor-bearing animals. We monitored the components by measuring their ability to stimulate messenger RNA (mRNA) release from isolated nuclei in a cell-free system of rat liver nuclei in fortified homologous cytosol. This in vitro test system exhibited near-normal in vivo nuclear RNA restriction. When added to the assay at a protein concentration of 3.0 mg/ml, dialyzed plasma from rats or mice with chemically induced transplantable or primary tumors stimulated mRNA release from 87% to more than 300% over control plasma from normal rats. Plasma from partially hepatectomized rats stimulated only 26% over control plasma. The test system derived from rat liver seemed to permit the monitoring of plasma from other species. Available evidence, particularly relating to tumor-host-interaction, suggests, but does not prove, that regulatory components are released from the tumor cells to the circulation.
mesh_terms: D000818:Animals; D001483:Base Sequence; D001798:Blood Proteins; D006528:Carcinoma, Hepatocellular / Q000097:blood; D002467:Cell Nucleus / Q000378:metabolism*; D002474:Cell-Free System; D003600:Cytosol / Q000378:metabolism; D005260:Female; D006498:Hepatectomy; D008099:Liver / Q000648:ultrastructure; D008113:Liver Neoplasms / Q000097:blood; D008115:Liver Regeneration; D046911:Macromolecular Substances / Q000097:blood*; D008297:Male; D008325:Mammary Neoplasms, Experimental / Q000097:blood; D009369:Neoplasms / Q000175:diagnosis; D009374:Neoplasms, Experimental / Q000097:blood*; D009693:Nucleic Acid Hybridization; D010949:Plasma / Q000032:analysis; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D012513:Sarcoma, Experimental / Q000097:blood
chemical_list: D001798:Blood Proteins; D046911:Macromolecular Substances; D012333:RNA, Messenger