Transport of sodium into apical membrane vesicles prepared from fetal sheep alveolar type II cells.
A method is described for isolating apical plasma membrane vesicles from fetal alveolar type II cells. The procedure yields purified apical membranes which are enriched 24-fold with the brush-border enzyme marker, alkaline phosphatase. Contamination of this fraction by basolateral membranes and organelles is minimal. Evidence for transport of Na+ into an intravesicular space is demonstrated by: (1) time-dependent uptake of Na+ with release of accumulated Na+ by treatment with detergent; (2) a linear inverse correlation between Na+ uptake and medium osmolarity. In addition, Na+ uptake is shown to be anion dependent (SCN- greater than Cl- greater than gluconate-) and sensitive to amiloride inhibition at a concentration of 1 mM.
Butcher
P A
PA
Department of Child Health, The University, Dundee, U.K.
Steele
L W
LW
Ward
M R
MR
Olver
R E
RE
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D000838:Anions; D001692:Biological Transport / Q000187:drug effects; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism; D002712:Chlorides / Q000494:pharmacology; D005942:Gluconates / Q000494:pharmacology; D007700:Kinetics; D017830:Octoxynol; D009994:Osmolar Concentration; D011092:Polyethylene Glycols / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000196:embryology* / Q000378:metabolism; D012756:Sheep; D012964:Sodium / Q000378:metabolism*; D013861:Thiocyanates / Q000494:pharmacology
D000838:Anions; D002712:Chlorides; D005942:Gluconates; D013861:Thiocyanates; D011092:Polyethylene Glycols; D000584:Amiloride; D017830:Octoxynol; D012964:Sodium; C031760:thiocyanate; C030691:gluconic acid