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Phorbol ester TPA inhibits the stimulation of bumetanide‐sensitive Na+/K+/Cl– transporter by different mitogens in quiescent BALB/c 3T3 mouse fibroblasts
Author(s) -
Snyder David,
Markus Miriam,
Atlan Henri,
Panet Rivka
Publication year - 1991
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041460318
Subject(s) - bumetanide , cotransporter , stimulation , phorbol , protein kinase c , chemistry , 3t3 cells , efflux , microbiology and biotechnology , biochemistry , endocrinology , medicine , phosphorylation , biology , sodium , transfection , organic chemistry , gene
In this study we examined the effect of the phorbol ester 12‐O‐tetradecanoyl‐phorbol‐13‐acetate (TPA) on the bumetanide‐sensitive Na+/K+/Cl– transporter in quiescent BALB/c 3T3 cells. We have shown that exposure of quiescent BALB/c 3T3 cultures to phorbol ester did not inhibit the basal bumetanide‐sensitive Rb+ influx or efflux. In fact, at high concentration (100 ng/ml), TPA slightly stimulated the bumetanide‐sensitive Rb+ influx and efflux. However, when the quiescent cultures were stimulated by serum or by defined growth factors, the stimulated fraction of the bumetanide‐sensitive Rb+ influx was drastically inhibited by exposure of the cells to the phorbol ester TPA. Based on the above findings, we propose that activation of protein kinase C by the phorbol ester TPA does not inhibit the Na+/K+/Cl– cotransport activity; however it does suppress only the growth‐factors‐stimulated fraction of the cotransport in quiescent BALB/c 3T3 cells. These data propose that activation of kinase C has a regulatory feedback effect on the stimulation of the Na+/K+/Cl– cotransport activity by growth factors.