In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 91, No. 17 ( 1994-08-16), p. 8205-8208
Kurzfassung:
Phosphate (Pi) reabsorption in renal proximal tubules involves Na+/Pi cotransport across the brush border membrane; its transport rate is influenced by the Na(+)-coupled transport of other solutes as well as by pH. In the present study, we have expressed a cloned rat renal brush border membrane Na+/Pi cotransporter (NaPi-2) in Xenopus laevis oocytes and have analyzed its electrophysiologic properties in voltage- and current-clamp studies. Addition of Pi to Na(+)-containing superfusates resulted in a depolarization of the membrane potential and, in voltage-clamped oocytes, in an inward current (IP). An analysis of the Na+ and/or Pi concentration dependence of IP suggested a Na+/Pi stoichiometry of 3:1. IP was increased by increasing the pH of the superfusate; this phenomenon seems to be mainly related to a lowering of the affinity for Na+ interaction by increasing H+ concentration. The present data suggest that known properties of Pi handling at the tubular/membrane level are "directly" related to specific characteristics of the transport molecule (NaPi-2) involved.
Materialart:
Online-Ressource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.91.17.8205
Sprache:
Englisch
Verlag:
Proceedings of the National Academy of Sciences
Publikationsdatum:
1994
ZDB Id:
209104-5
ZDB Id:
1461794-8
SSG:
11
SSG:
12
