title: 1,2-Dimethylhydrazine-induced alterations in colonic plasma membrane fluidity: restriction to the luminal region.
abstract: Recently, work in this laboratory has shown that changes in the 'dynamic' component of fluidity, lipid composition and phospholipid methylation activity of distal colonic brush-border membranes could be detected after administration of 1,2-dimethylhydrazine to rats of the Sherman strain for 5-15 weeks, i.e., before the development of colon cancer. The present experiments were therefore conducted to: determine whether similar 'premalignant' biochemical changes could be detected in basolateral membranes of Sherman rats treated with this agent; and clarify the relationship of these membrane changes to the malignant transformation process by examining the effect of 1,2-dimethylhydrazine on these biochemical parameters in colonic antipodal plasma membranes of rats of the Lobund-Wistar strain. This particular strain of rats has previously been shown to be total resistant to the induction of tumors by 1,2-dimethylhydrazine. The results of the present experiments demonstrate that similar biochemical alterations could not be detected in the colonic plasma membranes prepared from either strain of rat treated with 1,2-dimethylhydrazine. These data support the contention that the prior biochemical membrane alterations noted in brush-border membranes of 1,2-dimethylhydrazine-treated animals are, in fact, related to the malignant transformation process and, furthermore, are confined to the luminal surface of distal colonic epithelial cells.
mesh_terms: D019813:1,2-Dimethylhydrazine; D000230:Adenocarcinoma / Q000139:chemically induced; D000818:Animals; D002462:Cell Membrane / Q000032:analysis / Q000187:drug effects / Q000648:ultrastructure; D003106:Colon / Q000032:analysis / Q000187:drug effects / Q000648:ultrastructure*; D003110:Colonic Neoplasms / Q000139:chemically induced; D004127:Dimethylhydrazines / Q000494:pharmacology* / Q000633:toxicity; D004351:Drug Resistance; D007113:Immunity, Innate; D008297:Male; D008560:Membrane Fluidity / Q000187:drug effects*; D008563:Membrane Lipids / Q000032:analysis; D008745:Methylation; D008763:Methylhydrazines / Q000494:pharmacology*; D008871:Microvilli / Q000187:drug effects / Q000648:ultrastructure; D010743:Phospholipids / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains / Q000378:metabolism*
chemical_list: D004127:Dimethylhydrazines; D008563:Membrane Lipids; D008763:Methylhydrazines; D010743:Phospholipids; D019813:1,2-Dimethylhydrazine