Differential effects of brefeldin A on hormonally regulated Na+ transport in a model renal epithelial cell line.
Na+ transport in renal epithelia is regulated by a wide variety of endogenous and exogenous cellular factors. Although most natriferic agents have an action on the amiloride-sensitive Na+ channel, the biochemical pathways which precede activation of the channel remain incompletely defined. One approach to dissecting such intricate pathways is to perturb a specific cellular process and determine its importance in the postulated mechanism. The current studies examine the effect of brefeldin A (BFA), an inhibitor of the central vacuolar system, on basal as well as aldosterone-, insulin-, and forskolin-stimulated Na+ transport. In the A6 cell line, BFA had a time-dependent effect on basal transport. Aldosterone-induced Na+ transport was sensitive to BFA while insulin's action was only partially blocked and forskolin-stimulated Na+ transport was relatively resistant to the action of the inhibitor. These studies highlight differences as well as points of convergence in the natriferic pathways.
Coupaye-Gerard
B
B
Department of Medicine, University of Pennsylvania, Philadelphia.
Kim
H J
HJ
Singh
A
A
Blazer-Yost
B L
BL
D000450:Aldosterone / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D020126:Brefeldin A; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology*; D004848:Epithelium / Q000378:metabolism; D006728:Hormones / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D007668:Kidney / Q000378:metabolism*; D008954:Models, Biological; D012964:Sodium / Q000378:metabolism*; D014982:Xenopus laevis
D003517:Cyclopentanes; D006728:Hormones; D007328:Insulin; D005576:Colforsin; D020126:Brefeldin A; D000450:Aldosterone; D012964:Sodium