Abstract
It is thought that cysts in polycystic kidneys originate from nephron segments and function in a manner similar to the segment or origin. The indirect evidence for this derives from studies of microanatomy and cyst fluid composition. Cysts with low Na+ have been classified as distal, whereas cysts with high Na+ have been classified as proximal. In order to directly determine the transport characteristics of cyst epithelium, cysts from a human polycystic kidney were studied in vitro using Ussing chamber techniques. Composition of cyst fluid was determined in parallel with these studies. Cysts with low Na+ (gradient cysts) demonstrate characteristics consistent with distal nephron origin including elevated potential difference (PD), short-circuit current (Isc), and low conductance. PD and Isc of gradient cysts were amiloride sensitive. Nongradient cysts, however, require additional characterization. At least two types of nongradient cysts were identified, one with characteristics consistent with proximal nephron origin and another apparently without function. These studies are the first direct evidence for active transport of cysts from human polycystic kidney and provide strong evidence to support the concept that cysts function in the same manner as the nephron segment of origin.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Baert L. Hereditary polycystic kidney disease (adult form): a microdissection study of two cases at an early stage of the disease. Kidney Int. 1978 Jun;13(6):519–525. doi: 10.1038/ki.1978.75. [DOI] [PubMed] [Google Scholar]
- Benos D. J. Amiloride: a molecular probe of sodium transport in tissues and cells. Am J Physiol. 1982 Mar;242(3):C131–C145. doi: 10.1152/ajpcell.1982.242.3.C131. [DOI] [PubMed] [Google Scholar]
- Cuppage F. E., Huseman R. A., Chapman A., Grantham J. J. Ultrastructure and function of cysts from human adult polycystic kidneys. Kidney Int. 1980 Mar;17(3):372–381. doi: 10.1038/ki.1980.43. [DOI] [PubMed] [Google Scholar]
- Gardner K. D., Jr Composition of fluid in twelve cysts of a polycystic kidney. N Engl J Med. 1969 Oct 30;281(18):985–988. doi: 10.1056/NEJM196910302811804. [DOI] [PubMed] [Google Scholar]
- Grantham J. J. Polycystic kidney disease: a predominance of giant nephrons. Am J Physiol. 1983 Jan;244(1):F3–10. doi: 10.1152/ajprenal.1983.244.1.F3. [DOI] [PubMed] [Google Scholar]
- Huseman R., Grady A., Welling D., Grantham J. Macropuncture study of polycystic disease in adult human kidneys. Kidney Int. 1980 Sep;18(3):375–385. doi: 10.1038/ki.1980.148. [DOI] [PubMed] [Google Scholar]
- Jacobson H. R. Functional segmentation of the mammalian nephron. Am J Physiol. 1981 Sep;241(3):F203–F218. doi: 10.1152/ajprenal.1981.241.3.F203. [DOI] [PubMed] [Google Scholar]
- Macknight A. D., DiBona D. R., Leaf A. Sodium transport across toad urinary bladder: a model "tight" epithelium. Physiol Rev. 1980 Jul;60(3):615–715. doi: 10.1152/physrev.1980.60.3.615. [DOI] [PubMed] [Google Scholar]
- Nellans H. N., Frizzell R. A., Schultz S. G. Effect of acetazolamide on sodium and chloride transport by in vitro rabbit ileum. Am J Physiol. 1975 Jun;228(6):1808–1814. doi: 10.1152/ajplegacy.1975.228.6.1808. [DOI] [PubMed] [Google Scholar]
- Perrone R. D., Jenks S. L. Suppression of coupled Na-Cl absorption by aldosterone and dexamethasone in rat distal colon in vitro. Am J Physiol. 1984 Jun;246(6 Pt 2):F785–F793. doi: 10.1152/ajprenal.1984.246.6.F785. [DOI] [PubMed] [Google Scholar]
- Turnheim K., Frizzell R. A., Schultz S. G. Effects of anions on amiloride-sensitive, active sodium transport across rabbit colon, in vitro. Evidence for "trans-inhibition" of the Na entry mechanism. J Membr Biol. 1977 Oct 3;37(1):63–84. doi: 10.1007/BF01940924. [DOI] [PubMed] [Google Scholar]