Abstract
In the toad urinary bladder, antidiuretic hormone (ADH)-mediated changes in water permeability depend on exocytic insertion and endocytic retrieval of water channels into and from the apical membrane, respectively. Because GTP-binding proteins (G proteins) are well-recognized regulators of vesicular trafficking throughout the cell, we tested the hypothesis that drugs interfering with G protein would modify the hydrosmotic response to ADH and the ADH-regulated formation of endosomes, as assessed by luminal incorporation of a fluid-phase marker [fluorescein isothiocyanate (FITC)-dextran, 70 kDa]. Mastoparan (4 microM) and compound 48/80 (poly-p-methoxyphenylethylmethylamine; 50 micrograms/ml), added to the luminal side of the toad urinary bladder, as well as AlF3 added to the serosal side (400 microM), inhibited ADH- and 8-bromoadenosine 3',5'-cyclic monophosphate-induced transepithelial water flow by > 50% and simultaneously enhanced cellular incorporation of FITC-dextran by > 200%. The pattern of FITC-dextran uptake observed using fluorescence microscopy both in scraped cells and in the intact bladder was granular, suggesting fluid-phase endocytosis. Mastoparan and AlF3, which are both probes of G proteins, increased FITC-dextr...Continue Reading
References
Aug 1, 1979·Chemical & Pharmaceutical Bulletin·Y HiraiC Kitada
Jan 15, 1992·The Biochemical Journal·C P Wheeler-JonesK S Authi
Mar 27, 1992·Science·M I ColomboP D Stahl
Sep 1, 1992·Proceedings of the National Academy of Sciences of the United States of America·C OppiG P Tocchini Valentini
Sep 1, 1990·The Journal of Cell Biology·M AridorR Sagi-Eisenberg
Dec 1, 1990·Trends in Biochemical Sciences·W E Balch
Jan 1, 1990·Annual Review of Physiology·B D Gomperts
Sep 1, 1990·Trends in Pharmacological Sciences·M MousliY Landry
Sep 1, 1986·The Journal of Clinical Investigation·H W HarrisJ S Handler
Jan 1, 1985·The Journal of Membrane Biology·M ParisiJ Bourguet
Aug 1, 1982·Proceedings of the National Academy of Sciences of the United States of America·P C Sternweis, A G Gilman
Dec 3, 1993·Science·M AridorR Sagi-Eisenberg
Nov 15, 1993·Biochemical and Biophysical Research Communications·M DanilenkoY Sharoni
Apr 1, 1993·Nature·S W Pimplikar, K Simons
Jul 1, 1993·Molecular and Cellular Endocrinology·P M JonesC P Wheeler-Jones
Mar 1, 1993·The Biochemical Journal·T H Lillie, B D Gomperts
Sep 1, 1958·The Journal of Endocrinology·P J BENTLEY
May 1, 1993·Trends in Cell Biology·S L Schmid
Dec 1, 1969·The Journal of Membrane Biology·M MamelakI S Edelman