Abstract
Volume changes due to osmotic flow in the distal portion of proximal tubules of Necturi were measured by the split oil drop technique. In agreement with previous findings no volume flow was induced by NaCl concentrations close to 60 mM. The tubule wall was found to be permeable to plasma electrolytes, which have an apparent reflection coefficient of 0.69. The mean apparent hydraulic conductivity was 0.33 x 10-11 cm3/dyne sec, comparable with other epithelia. A number of lipid-insoluble nonelectrolytes of widely varying molecular size had apparent reflection coefficients of about 0.5. In view of the insensitivity to molecular size it seems likely that apparent reflection coefficients determined from tubular volume changes depend primarily on the porosity of the intercellular barrier closest to the lumen and give little information about the subsequent fate of the test substances.
Full Text
The Full Text of this article is available as a PDF (972.3 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Maude D. L., Shehadeh I., Solomon A. K. Sodium and water transport in single perfused distal tubules of Necturus kidney. Am J Physiol. 1966 Oct;211(4):1043–1049. doi: 10.1152/ajplegacy.1966.211.4.1043. [DOI] [PubMed] [Google Scholar]
- OKEN D. E., WHITTEMBURY G., WINDHAGER E. E., SOLOMON A. K. Single proximal tubules of Necturus kidney. V. Unidirectional sodium movement. Am J Physiol. 1963 Mar;204:372–376. doi: 10.1152/ajplegacy.1963.204.3.372. [DOI] [PubMed] [Google Scholar]
- SCHULTZ S. G., SOLOMON A. K. Determination of the effective hydrodynamic radii of small molecules by viscometry. J Gen Physiol. 1961 Jul;44:1189–1199. doi: 10.1085/jgp.44.6.1189. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Scott W. N., Maude D. L., Shehadeh I., Solomon A. K. Transtubular movement of albumin in Necturus kidney. Am J Physiol. 1966 Oct;211(4):1039–1042. doi: 10.1152/ajplegacy.1966.211.4.1039. [DOI] [PubMed] [Google Scholar]
- WHITTEMBURY G., OKEN D. E., WINDHAGER E. E., SOLOMON A. K. Single proximal tubules of Necturus kidney. IV. Dependence of H20 movement on osmotic gradients. Am J Physiol. 1959 Nov;197:1121–1127. doi: 10.1152/ajplegacy.1959.197.5.1121. [DOI] [PubMed] [Google Scholar]
- WINDHAGER E. E., WHITTEMBURY G., OKEN D. E., SCHATZMANN H. J., SOLOMON A. K. Single proximal tubules of the Necturus kidney. III. Dependence of H2O movement on NaCl concentration. Am J Physiol. 1959 Aug;197:313–318. doi: 10.1152/ajplegacy.1959.197.2.313. [DOI] [PubMed] [Google Scholar]