title: Membrane fluidity and phospholipid composition in relation to sulfur amino acid intake in brush border membranes of rat kidney.
abstract: The transport of ions and solutes across biological membranes may relate to changes in the lipid microenvironment of the membrane which could alter the activity or configuration of transport sites. Changes in the sulfur amino acid content of diets fed to young rats results in an increase in Na+-taurine symport in brush border membranes isolated from animals fed a low sulfur amino acid diet and a reduction in symport after a high taurine diet in comparison to uptake by membranes from normally fed animals ("the renal adaptive response"). We explored the possibility that diet-induced changes in brush border membrane symport relate to altered membrane fluidity and phospholipid composition in response to diet. An Arrhenius plot of initial rate (15 s) taurine uptake in breakpoint at 22 degrees C, but no change in relation to dietary alteration. Fluorescence polarization data employing the probe 1-6-diphenyl-1,3,5-hexatriene best fits a two-phase linear model employing a computer model fitting program. Dietary manipulations did not change the breakpoint upper segment slope or lower segment slope after incubating fresh membranes with DPH over the temperature range 4-56 degrees C. No change was evident in membrane phospholipid composition in relation to diet. This study indicates that the changes in initial rate Na+-taurine symport in relation to diet are less likely to be due to changes in the configuration of the transporter from an alteration of the lipid microenvironment of the membrane.
mesh_terms: D000603:Amino Acids, Sulfur / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D004032:Diet; D007668:Kidney / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008560:Membrane Fluidity; D008563:Membrane Lipids / Q000378:metabolism*; D008871:Microvilli / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013654:Taurine / Q000378:metabolism; D013696:Temperature
chemical_list: D000603:Amino Acids, Sulfur; D008563:Membrane Lipids; D010743:Phospholipids; D013654:Taurine