title: The synthesis of sphingomyelin in the Morris hepatomas 7777 and 5123D is restricted to the plasma membrane.
abstract: The site of sphingomyelin synthesis in the rapidly growing Morris hepatomas 7777 and 5123D was determined by incubating plasma membrane, mitochondrial and microsomal membrane fractions with vesicles of phosphatidyl[methyl-14C]choline in the presence of phosphatidylcholine transfer protein. In agreement with a previous study on rat liver (Voelker, D.R. and Kennedy, E.P., 1982, Biochemistry 21, 2753-2759) we have demonstrated that sphingomyelin synthesis in these hepatomas is restricted to the plasma membrane. The greatly elevated sphingomyelin content of mitochondria and microsomes (Hostetler, K.Y., Zenner, B.D. and Morris, H.P., 1979, Cancer Res. 39, 2978-2983) suggests that rapidly growing hepatomas, in contrast to liver, have an effective mechanism of intracellular sphingomyelin transfer.
mesh_terms: D000727:Androgen-Binding Protein; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism; D049294:Phospholipid Transfer Proteins; D060789:Prostatein; D051381:Rats; D011915:Rats, Inbred BUF; D060765:Secretoglobins; D013109:Sphingomyelins / Q000096:biosynthesis*; D014598:Uteroglobin; D060788:Mammaglobin B
chemical_list: D000727:Androgen-Binding Protein; D002352:Carrier Proteins; D049294:Phospholipid Transfer Proteins; D060789:Prostatein; D060765:Secretoglobins; D013109:Sphingomyelins; D014598:Uteroglobin; C511484:Scgb1d2 protein, rat; C511483:Scgb1d4 protein, rat; C556468:Scgb2a1 protein, rat; D060788:Mammaglobin B