TY - JOUR
T1 - Modulation of sulfate renal transport by alterations in cell membrane fluidity
AU - Lee, Hwa Jeong
AU - Balasubramanian, Sathyamangalam V.
AU - Murer, Heini
AU - Biber, Jurg
AU - Morris, Marilyn E.
N1 - Funding Information:
This work was supported by NSF grant IBN 9629470 and grants from the Western New York Kidney Foundation/Upstate Transplant Services and the Kapoor Charitable Foundation at SUNY at Buffalo (for M.E.M.). Additional support was provided by the Swiss National Science Foundation (for H.M.).
PY - 1999/10
Y1 - 1999/10
N2 - Changes in membrane fluidity have been shown to alter the sodium- dependent renal transport of glucose and phosphate; however, this has not been examined for sodium/sulfate cotransport in the renal proximal tubule. Sodium/sulfate cotransport regulates the homeostasis of sulfate in mammals. The objective of this study was to investigate the influence of alterations of membrane fluidity on sodium-coupled sulfate transport in the Madin-Darby canine kidney cells, which have been stably transfected with sodium/sulfate cotransporter (NaSi-1) cDNA (MDCK-Si). Preincubation of cells with 0.2 mM cholesterol significantly decreased the V(max) for sodium/sulfate cotransport (13.69 ± 1.11 vs 10.15 ± 1.17 nmol/mg protein/5 min, mean ± SD, n = 4, p< 0.01) with no significant alteration in K(m). The addition of benzyl alcohol (20 mM) to cells increased the V(max) of sulfate uptake by 20% (11.97 ± 0.91 vs 14.35 ± 0.56 nmol/mg protein/5 min, mean ±SD, n = 3, p < 0.05) with no significant change in K(m). Membrane fluidity, as measured by the fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH), was significantly increased in MDCK-Si cells treated with 20 mM benzyl alcohol and decreased in the cells preincubated with 0.2 mM cholesterol, compared with control cells. Our results suggest that alterations in membrane fluidity that may occur as a result of disease states, aging, and pregnancy may play an important role in the modulation of renal sodium/sulfate cotransport.
AB - Changes in membrane fluidity have been shown to alter the sodium- dependent renal transport of glucose and phosphate; however, this has not been examined for sodium/sulfate cotransport in the renal proximal tubule. Sodium/sulfate cotransport regulates the homeostasis of sulfate in mammals. The objective of this study was to investigate the influence of alterations of membrane fluidity on sodium-coupled sulfate transport in the Madin-Darby canine kidney cells, which have been stably transfected with sodium/sulfate cotransporter (NaSi-1) cDNA (MDCK-Si). Preincubation of cells with 0.2 mM cholesterol significantly decreased the V(max) for sodium/sulfate cotransport (13.69 ± 1.11 vs 10.15 ± 1.17 nmol/mg protein/5 min, mean ± SD, n = 4, p< 0.01) with no significant alteration in K(m). The addition of benzyl alcohol (20 mM) to cells increased the V(max) of sulfate uptake by 20% (11.97 ± 0.91 vs 14.35 ± 0.56 nmol/mg protein/5 min, mean ±SD, n = 3, p < 0.05) with no significant change in K(m). Membrane fluidity, as measured by the fluorescence polarization of 1,6-diphenyl 1,3,5-hexatriene (DPH), was significantly increased in MDCK-Si cells treated with 20 mM benzyl alcohol and decreased in the cells preincubated with 0.2 mM cholesterol, compared with control cells. Our results suggest that alterations in membrane fluidity that may occur as a result of disease states, aging, and pregnancy may play an important role in the modulation of renal sodium/sulfate cotransport.
UR - http://www.scopus.com/inward/record.url?scp=0004982625&partnerID=8YFLogxK
U2 - 10.1021/js990114c
DO - 10.1021/js990114c
M3 - Article
C2 - 10514342
AN - SCOPUS:0004982625
VL - 88
SP - 976
EP - 980
JO - Journal of Pharmaceutical Sciences
JF - Journal of Pharmaceutical Sciences
SN - 0022-3549
IS - 10
ER -