TY - JOUR
T1 - Protein kinase C regulation of p-glycoprotein-mediated xenobiotic secretion in renal proximal tubule
AU - Miller, David S.
AU - Sussman, Caroline R.
AU - Renfro, J. Larry
PY - 1998/11
Y1 - 1998/11
N2 - Fluorescence microscopy, fluorescent substrates [daunomycin and a fluorescent cyclosporin A (CSA) derivative] and digital image analysis were used to examine the role of protein kinase C (PKC) in the control of p- glycoprotein in killifish renal proximal tubules. PKC activators, phorbol ester (phorbol 12-myristate 13-acetate, PMA) and dioctylglycerol, reduced luminal drug accumulation, and protein kinase inhibitors, staurosporine and 1-(5-isoquinolinylsulfonyl)-2methylpiperazine (H-7), increased luminal accumulation; a PMA analog that does not activate PKC was without effect. PMA effects were blocked by staurosporine. The increase in luminal fluorescence caused by staurosporine was blocked by the p-glycoprotein substrate, CSA, indicating that this component of transport was indeed mediated by p- glycoprotein. Neither PMA, dioctylglycerol, nor protein kinase inhibitors altered cellular drug accumulation. Finally, in primary cultures of flounder proximal tubule cells, PMA decreased transepithelial [3H]daunomycin secretion. This pharmacological approach demonstrates that in telcost renal proximal tubule, p-glycoprotein-mediated xenobiotic secretion is negatively correlated with changes in PKC activity, a finding that conflicts with results from studies using mammalian tumor cells that express p-glycoprotein.
AB - Fluorescence microscopy, fluorescent substrates [daunomycin and a fluorescent cyclosporin A (CSA) derivative] and digital image analysis were used to examine the role of protein kinase C (PKC) in the control of p- glycoprotein in killifish renal proximal tubules. PKC activators, phorbol ester (phorbol 12-myristate 13-acetate, PMA) and dioctylglycerol, reduced luminal drug accumulation, and protein kinase inhibitors, staurosporine and 1-(5-isoquinolinylsulfonyl)-2methylpiperazine (H-7), increased luminal accumulation; a PMA analog that does not activate PKC was without effect. PMA effects were blocked by staurosporine. The increase in luminal fluorescence caused by staurosporine was blocked by the p-glycoprotein substrate, CSA, indicating that this component of transport was indeed mediated by p- glycoprotein. Neither PMA, dioctylglycerol, nor protein kinase inhibitors altered cellular drug accumulation. Finally, in primary cultures of flounder proximal tubule cells, PMA decreased transepithelial [3H]daunomycin secretion. This pharmacological approach demonstrates that in telcost renal proximal tubule, p-glycoprotein-mediated xenobiotic secretion is negatively correlated with changes in PKC activity, a finding that conflicts with results from studies using mammalian tumor cells that express p-glycoprotein.
KW - Confocal microscopy
KW - Fluorescence microscopy
KW - Killifish
KW - Multidrug resistance transporter
KW - Phorbol ester
KW - Renal secretion
KW - Staurosporine
KW - Teleost fish
KW - Winter flounder
UR - http://www.scopus.com/inward/record.url?scp=0031730608&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0031730608&partnerID=8YFLogxK
U2 - 10.1152/ajprenal.1998.275.5.f785
DO - 10.1152/ajprenal.1998.275.5.f785
M3 - Article
C2 - 9815136
AN - SCOPUS:0031730608
SN - 1931-857X
VL - 275
SP - F785-F795
JO - American Journal of Physiology - Renal Physiology
JF - American Journal of Physiology - Renal Physiology
IS - 5 44-5
ER -