The presence of H+,K(+)-ATPase in the crypt of rabbit distal colon demonstrated with monoclonal antibodies against gastric H+,K(+)-ATPase.
Indirect evidence indicates the presence of an active H+/K+ antiporter for the secretion of acid in the distal colon. It was examined whether the H+/K+ antiporter in the rabbit distal colon was hydrogen-potassium-stimulated adenosine triphosphatase (H+,K(+)-ATPase), which acts as a proton pump in the gastric mucosa. For this purpose, four monoclonal antibodies against hog gastric H+,K(+)-ATPase were raised. Three monoclonal antibodies dose-dependently inhibited the ouabain-insensitive gastric ATP-ase activity. Antibody HK4001 completely inhibited the ATPase activity. In indirect immunofluorescence studies, all four monoclonal antibodies stained H+,K(+)-ATPase in gastric mucosae of various animal species. Two monoclonal antibodies including antibody HK4001 cross-reacted with H+,K(+)-ATPase located in crypts of the transverse and descending colon and rectum of rabbits. Because the other two antibodies did not cross-react with the H+,K(+)-ATPase in the colon, this colonic enzyme is similar but not identical to gastric H+,K(+)-ATPase. On the other hand, HK4001 and SCH 28080 did not inhibit ouabain-sensitive K(+)-dependent ATPase activity in the guinea pig distal colon, and the antibodies did not stain the enzyme in the tissue. Therefore, ouabain-sensitive H+/K+ antiporter in the guinea pig is not similar to ouabain-insensitive rabbit colonic H+,K(+)-ATPase.
Takeguchi
M
M
Faculty of Pharmaceutical Sciences, Toyama Medical and Pharmaceutical University, Japan.
Asano
S
S
Tabuchi
Y
Y
Takeguchi
N
N
D000251:Adenosine Triphosphatases / Q000032:analysis* / Q000037:antagonists & inhibitors; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D003106:Colon / Q000187:drug effects / Q000201:enzymology*; D003429:Cross Reactions; D006168:Guinea Pigs; D017506:H(+)-K(+)-Exchanging ATPase; D007093:Imidazoles / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011817:Rabbits; D013270:Stomach / Q000201:enzymology
D000911:Antibodies, Monoclonal; D007093:Imidazoles; C035235:Sch 28080; D010042:Ouabain; D000251:Adenosine Triphosphatases; D017506:H(+)-K(+)-Exchanging ATPase