Two distinct K(+)-ATPase activities in rabbit distal colon.
The distribution of K(+)-ATPase activity in surface and crypt cells from rabbit distal colon was studied. Separation of surface and crypt cells was validated using the multidrug resistance gene (mdr 1) product, P-glycoprotein, as marker for differentiated surface epithelial cells. Western blot analysis revealed a 6-fold higher expression level of P-glycoprotein in colonic surface cells. K(+)-stimulated ouabain-insensitive ATPase activity was present in surface and in crypt cells. In surface cells, this K(+)-ATPase activity was only partly inhibitable by 10 microM SCH 28080, while in crypt cells K(+)-ATPase activity equalled SCH 28080-sensitive ATPase activity. These results strongly suggest the presence of two distinct K(+)-ATPases in colonic epithelial cells.
Abrahamse
S I
SI
Department of Cell Physiology, University of Nijmegen, The Netherlands.
De Jonge
H R
HR
Bindels
R J
RJ
Van Os
C H
CH
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000032:analysis; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D027682:Cation Transport Proteins; D002469:Cell Separation; D003106:Colon / Q000166:cytology / Q000201:enzymology*; D004848:Epithelium / Q000201:enzymology; D005260:Female; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D011188:Potassium / Q000008:administration & dosage; D011817:Rabbits; D014018:Tissue Distribution
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D027682:Cation Transport Proteins; D007093:Imidazoles; C035235:Sch 28080; D000251:Adenosine Triphosphatases; C022761:potassium transporting ATPase; D011188:Potassium