Open AccessOuabain-insensitive, Na+-stimulated ATPase of several rat tissues: activity during a 24 h period
Author(s) -
Alisha Wehdnesday Bernardo Reyes,
Galindo Mm,
Lázaro Hernández García,
D Segura-Pena,
Celso CarusoNeves,
Antonio Eblén-Zajjur,
Teresa Proverbio,
Reinaldo Marı́n,
Fulgencio Proverbio
Publication year - 2009
Publication title -
physiological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 70
eISSN - 1802-9973
pISSN - 0862-8408
DOI - 10.33549/physiolres.931509
Subject(s) - ouabain , atpase , chemistry , kidney , cortex (anatomy) , enzyme , medicine , endocrinology , enzyme assay , sodium , biology , biochemistry , organic chemistry , neuroscience
Rhythmic daily changes in the Na,K-ATPase activity have beenpreviously described for rat kidney cortex, showing two peaks: at0900 h and 2100 h, and two valleys: at 1500 h and 0100 h -0300 h. The oscillations in Na,K-ATPase activity are produced byan inhibitor, which binds the enzyme and is present in the ratblood plasma at valley times and absent or at very lowconcentrations at peak times. Since it has been demonstratedthat active Na+ extrusion from the cells of several tissuesdepends not only on the Na,K-ATPase but also on the ouabaininsensitive Na-ATPase, we studied the activity of this latter enzyme of several rat tissues, i.e., kidney cortex, small intestine, liver, heart and red blood cells along the day. None of thesetissues showed any variation of their Na-ATPase activity alongthe day. Preincubation of kidney cortex homogenates obtained at0900 h, with blood plasma drawn at 0900 h and 1500 h, did notmodify the Na-ATPase activity. Our results indicate that the NaATPase activity does not oscillate along the day. These results are in agreement with the idea that the Na-ATPase could partially compensate the Na+ transport affected by oscillations of theNa,K-ATPase activity.