Calonge, ML , DE LA HORRA PADILLA, CARMEN, Cano, M , SanchezAguayo, I , Ilundain, AA
Si
Pflugers Arch.
Article
Científica
2.58
01/01/1997
A1997WH69300014
This study sought to investigate the presence and characteristics of K+-ATPase activity in chicken intestinal epithelia. A cytochemical method revealed Na+ independent, ouabain-sensitive, K+-ATPase activity in the apical, but not in the basolateral, membrane of chicken colonic and caecal epithelial cells. KS-ATPase activity was not observed in the small intestine. The measurement of K+-activated pNPPase activity was used to characterize the K+-ATPase activity evidenced by the cytochemical method. In addition, K+ and NH4+, but neither Na+ nor Li+, could activate pNPPase activity in chicken intestinal epithelia. Vanadate abolished ouabain-sensitive, K+-activated pNPPase activity in the three membrane preparations tested, whereas oligomycin and SCH 28080 were without effect. The K-m for K+ and the ouabain IC50 values for the apical colonic and caecal K+-activated pNPPase activity were higher than those measured for K+-activated pNPPase activity measured in the basolateral membrane of chicken jejunal enterocytes. The results indicate that the apical membranes of chicken colon and caecum possess Naf-independent, ouabain-sensitive K+-activated-ATPase activity.
K+-ATPase; intestine; epithelia; chicken