Sp. Kelly et Cm. Wood, Effect of cortisol on the physiology of cultured pavement cell epithelia from freshwater trout gills, AM J P-REG, 281(3), 2001, pp. R811-R820
Citations number
44
Categorie Soggetti
Physiology
Journal title
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
Cortisol had dose-dependent effects on the electrophysiological, permeabili
ty, and ion-transporting properties of cultured pavement cell epithelia der
ived from freshwater rainbow trout gills and grown on cell culture filter s
upports. Under both symmetrical (L15 media apical/L15 media basolateral) an
d asymmetrical (freshwater apical/L15 media basolateral) culture conditions
, cortisol treatment elevated transepithelial resistance, whereas permeabil
ity of epithelia to a paracellular permeability marker (polyethylene glycol
-4000) decreased. Cortisol did not alter the Na+-K+-ATPase activity or the
total protein content of the cultured preparations. During 24-h exposure to
asymmetrical conditions, the net loss rates of both Na+ and Cl- to the wat
er decreased with increasing cortisol dose, an important adaptation to dilu
te media. Unidirectional Na+ and Cl- flux measurements and the application
of the Ussing flux-ratio criterion revealed cortisol-induced active uptake
of both Na+ and Cl- under symmetrical culture conditions together with an i
ncrease in transepithelial potential (positive on the basolateral side). Un
der asymmetrical conditions, cortisol did not promote active ion transport
across the epithelium. These experiments provide evidence for the direct ac
tion of cortisol on cultured pavement cell epithelia and, in particular, em
phasize the importance of cortisol for limiting epithelial permeability.