Radiotracer studies of cystic fibrosis transmembrane conductance regulator expressed in Xenopus oocytes

T. Ohrui, W. Skach, M. Thompson, J. Matsumoto-Pon, C. Calayag, Jonathan Widdicombe

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

We measured fluxes of radiotracers in Xenopus oocytes expressing the cystic fibrosis transmembrane conductance regulator (CFTR). Addition of adenosine 3',5'-cyclic monophosphate (cAMP)-elevating agents [forskolin and 3-isobutyl-1-methylxanthine (I/F)] led to large increases in uptake of 36Cl, 125I, and 82Br into oocytes expressing wild-type CFTR or ΔF508 CFTR but not sham-injected oocytes. I/F also stimulated halide efflux from CFTR and ΔF508 oocytes in the sequence Cl > Br > I. cAMP-induced increases in 36Cl efflux from ΔF508 oocytes were ~20% of those in CFTR oocytes. Increases in halide efflux were blocked by diphenylamine-2-carboxylic acid but not by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. The phorbol ester, phorbol 12-myristate 13-acetate, also stimulated 36Cl efflux from CFTR oocytes. ATP uptakes into CFTR and sham oocytes were similar, and both were reduced by I/F. However, ATP uptake into I/F-treated CFTR oocytes was slightly greater (~40%) than into I/F-treated sham oocytes. Urea uptake into CFTR and sham oocytes was similar and in both cases was increased by I/F. However, the I/F-induced increase in urea uptake into CFTR oocytes was significantly greater than for sham oocytes. I/F stimulated formate uptake into CFTR oocytes but not into sham oocytes. Fluxes of 22Na, 86Rb, 35SO4, 32PO4, and mannitol were unaltered by expression and activation of CFTR.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume266
Issue number6 35-6
StatePublished - 1994
Externally publishedYes

Fingerprint

Cystic Fibrosis Transmembrane Conductance Regulator
Xenopus
Oocytes
formic acid
Urea
Adenosine Triphosphate
Fluxes
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
1-Methyl-3-isobutylxanthine
Phorbol Esters
Mannitol
Colforsin
Cyclic AMP
Acetates

Keywords

  • formate transport
  • halide selectivity
  • urea permeability

ASJC Scopus subject areas

  • Cell Biology
  • Clinical Biochemistry
  • Physiology

Cite this

Radiotracer studies of cystic fibrosis transmembrane conductance regulator expressed in Xenopus oocytes. / Ohrui, T.; Skach, W.; Thompson, M.; Matsumoto-Pon, J.; Calayag, C.; Widdicombe, Jonathan.

In: American Journal of Physiology - Cell Physiology, Vol. 266, No. 6 35-6, 1994.

Research output: Contribution to journalArticle

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