{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,7]],"date-time":"2026-02-07T17:57:03Z","timestamp":1770487023781,"version":"3.49.0"},"reference-count":0,"publisher":"American Physiological Society","issue":"1","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[1994,1,1]]},"abstract":"<jats:p> Over time, Xenopus laevis changed from producing stage V and VI oocytes with little native Na(+)-K(+)-2Cl- cotransport activity to those with substantial activity. In oocytes with high endogenous activity, K+ uptake, using the tracer 86Rb+ was approximately 20 pmol.min-1.oocyte-1 in the presence of blockers of Na(+)-K(+)-ATPase and conductive K+ transport. Bumetanide (10 microM) inhibited &gt; 90% of this uptake, suggesting involvement of Na(+)-K(+)-2Cl- cotransport. This was confirmed by two observations that are found in this cotransporter in other tissues: 1) The related diuretics, thiobenzmetanide [50% inhibitory concentration (IC50), 2 x 10(-11) M] &gt; bumetanide (IC50, 7 x 10(-8) M) &gt; furosemide (IC50, 2.5 x 10(-6) M) inhibited the cotransporter in a dose-dependent manner. 2) There was little uptake of K+ in the absence of extracellular Na+ or Cl-. Halving medium osmolarity to 92 mosM decreased bumetanide-sensitive K+ uptake by approximately 75%, whereas a doubling of medium osmolarity increased it by approximately 50%. The cotransport activity was increased fourfold by the phosphatase inhibitor calyculin A (200 nM) but was unaffected by 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate, 8-bromoguanosine 3',5'-cyclic monophosphate, ATP, ionomycin, or okadaic acid. Both the photoaffinity bumetanide analogue, 4-[3H]benzoyl-5-sulfamoyl-3-(3-thenyloxy)benzoic acid, and an antiserum raised against Ehrlich ascites cell cotransporter specifically labeled an approximately 140-kDa oocyte membrane protein. These results demonstrated that, in addition to the Na+ pump and K+ channels, K+ uptake in Xenopus oocytes occurs via a loop-diuretic-sensitive Na(+)-K(+)-2Cl- cotransporter.(ABSTRACT TRUNCATED AT 250 WORDS) <\/jats:p>","DOI":"10.1152\/ajpcell.1994.266.1.c284","type":"journal-article","created":{"date-parts":[[2017,12,24]],"date-time":"2017-12-24T14:34:48Z","timestamp":1514126088000},"page":"C284-C292","source":"Crossref","is-referenced-by-count":41,"title":["Characterization of the endogenous Na(+)-K(+)-2Cl- cotransporter in Xenopus oocytes"],"prefix":"10.1152","volume":"266","author":[{"given":"W.","family":"Suvitayavat","sequence":"first","affiliation":[{"name":"Department of Physiology and Biophysics, University of Illinois atChicago 60612."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"H. C.","family":"Palfrey","sequence":"additional","affiliation":[{"name":"Department of Physiology and Biophysics, University of Illinois atChicago 60612."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"Haas","sequence":"additional","affiliation":[{"name":"Department of Physiology and Biophysics, University of Illinois atChicago 60612."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"P. B.","family":"Dunham","sequence":"additional","affiliation":[{"name":"Department of Physiology and Biophysics, University of Illinois atChicago 60612."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"F.","family":"Kalmar","sequence":"additional","affiliation":[{"name":"Department of Physiology and Biophysics, University of Illinois atChicago 60612."}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M. C.","family":"Rao","sequence":"additional","affiliation":[{"name":"Department of Physiology and Biophysics, University of Illinois atChicago 60612."}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"24","container-title":["American Journal of Physiology-Cell Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.physiology.org\/doi\/pdf\/10.1152\/ajpcell.1994.266.1.C284","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T19:40:33Z","timestamp":1718653233000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.1994.266.1.C284"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1994,1,1]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1994,1,1]]}},"alternative-id":["10.1152\/ajpcell.1994.266.1.C284"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.1994.266.1.c284","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[1994,1,1]]}}}