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Science 17 March 1972:
Vol. 175. no. 4027, pp. 1261 - 1264
DOI: 10.1126/science.175.4027.1261
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Articles

Activities of Sodium and Potassium Ions in Epithelial Cells of Small Intestine

Chin O. Lee 1 and W. McD. Armstrong 1

1 Department of Physiology, Indiana University School of Medicine, Indianapolis 46202

Intracellular molar Na+ activity (aNa), measured with cation-selective glass microelectrodes, in epithelial cells of isolated bullfrog small intestine immersed at 26°C in a sodium sulfate Ringer solution containing mannitol was 0.0144 ± 0.0031 (average value plus or minus standard deviation). The corresponding K+ activity (aK) was 0.0854 ± 0.0060. Combination of these values with previous estimates of intracellular Na+ and K+ concentrations under identical conditions indicated that a substantial fraction of the cellular Na+ is in an osmotically inactive state. When the cells were exposed to a Ringer solution in which 26 millimoles of mannitol per liter were replaced by 3-O-methyl glucose, highly significant decreases in aK and aNa were observed. The decrease in aK was proportionately larger than the corresponding decrease in aNa.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Sodium-coupled sugar transport: effects on intracellular sodium activities and sodium-pump activity.
R. Hudson and S. Schultz (1984)
Science 224, 1237-1239
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