K(+)-ATPase-mediated Rb+ transport in rat collecting tubule: modulation during K+ deprivation.
Am J Physiol
; 260(6 Pt 2): F800-5, 1991 Jun.
Article
en En
| MEDLINE
| ID: mdl-1829329
ABSTRACT
To evaluate the involvement of K(+)-ATPase activity in K+ transport in the terminal segments of the rat nephron, we searched for the existence of a component of Rb+ uptake into microdissected segments of collecting tubule associated with the activity of this ATPase. Results indicated that K(+)-ATPase is stimulated by K+ and by Rb+ in a similar fashion and that it is specifically inhibited by the imidazopyridine Sch 28080 (apparent affinity approximately 5 x 10(-7) M). In both cortical and outer medullary collecting tubules (CCT and MCT) of normal rats, 10(-4) M Sch 28080 significantly inhibited the initial rate of Rb+ uptake. Sch 28080-sensitive Rb+ uptake in these two nephron segments was not altered by ouabain, as K(+)-ATPase activity. Finally, both K(+)-ATPase activity and Sch 28080-sensitive Rb+ uptake were increased by similar factors in the CCT and MCT of rats fed a K(+)-depleted diet for 3 days. In these two nephron segments, the apparent stoichiometry of K(+)-ATPase was 1 Rb+1 ATP. These results demonstrate that K(+)-ATPase reflects the activity of a K+ pump that is pharmacologically similar to the gastric H(+)-K+ pump.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Rubidio
/
Adenosina Trifosfatasas
/
Túbulos Renales Colectores
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol
Año:
1991
Tipo del documento:
Article