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Transport of Weak Electrolytes

Gerhard Rechkemmer

10.1002/cphy.cp060415

Source: Supplement 19: Handbook of Physiology, The Gastrointestinal System, Intestinal Absorption and Secretion

Originally published: 1991

Published online: January 2011

Full Article on Wiley Online Library



Abstract

The sections in this article are:

1 General Principles
1.1 Ionization and pH
1.2 Polarity and Partition Coefficient
1.3 Determinants of Passive Transport
2 Unstirred Layer—A Diffusion Barrier
3 Acid Microclimate
4 Paracellular Pathway
5 Apical and Basolateral Membrane Properties
5.1 Active or Passive Transport of Short‐Chain Fatty Acids?
5.2 Lipid Composition
5.3 Three‐Compartment Model
6 Subepithelial Barrier
7 Conclusions
Figure 1. Figure 1.

Compartments and barriers in weak electrolyte transport.
Figure 2. Figure 2.

pH dependence of weak electrolyte absorption, partition, and dissociation. Arrow, direction of shift of curve observed in transport experiments.
Figure 3. Figure 3.

pH dependence of weak electrolyte partitioning. Kni, partition coefficient of nonionized form; Ki, partition coefficient of ionized form. Curves calculated according to Equation 14 with pKa = 4.8.
Figure 4. Figure 4.

Shift of pH‐partition curves with pKa. Kni, partition coefficient of nonionized form; Ki, partition coefficient of ionized form.
Figure 5. Figure 5.

pH dependence of n‐octanol/buffer partition coefficients (Kapp) of acetic acid (filled triangles) (G. Rechkemmer, unpublished data) and bromoamiloride (filled circles) (G. Rechkemmer and D. J. Benos, unpublished data). Curves are fitted by nonlinear least‐squares regression analysis by using Equation 14. (Acetic acid data were weighted for the regression analysis.)
Figure 6. Figure 6.

Dependence of apparent partition coefficient on chain length of homologous series of short‐chain fatty acids. Open circles, n‐octanol/water partition; open triangles, hexadecane/water partition; Kapp, apparent partition coefficient. [Data from Stein 129.]
Figure 7. Figure 7.

Dependence of n‐octanol/water partition coefficients and clearance on chain length of a homologous series of short‐chain fatty acids. Clearance was calculated as net flux/mean solute concentration and referred to mucosal dry weight. Asterisk, n‐octanol/water partition coefficients 129; open circles, data from guinea pig proximal colon 99; open squares, data from guinea pig distal colon 99; Kapp, apparent partition coefficient. Lines were calculated by linear regression, slopes ( ± SD): partition coefficients, 1.258 ± 0.076, r = 1.0; proximal colon, 0.148 ± 0.013, r = 0.9925; distal colon, 0.453 ± 0.098, r = 0.9998.
Figure 8. Figure 8.

Nonionic diffusion and parallel channel models of weak electrolyte transport. NI, nonionic form; I, ionized form.

[Adapted from Jackson et al. 54.]
Figure 9. Figure 9.

Schematic representation of unstirred layers as diffusion barriers on both sides of a membrane. Concentration profiles are idealized; in reality they are curvilinear instead of linear as shown. C1 and C2, concentrations in bulk phase; Cm1 and Cm2, concentrations immediately adjacent to membrane; P1, P2, and Pm, permeabilities of unstirred layers and membrane, respectively; d1, d2, and dm, diffusion coefficients of unstirred layers and membrane, respectively.

[Adapted from Macey 83.]
Figure 10. Figure 10.

Diagrammatic representation of uptake of a homologous series of saturated fatty acids under circumstances where there is no diffusion‐barrier resistance (curve A) or where barrier exerts modest (curve B) or high (curve C) degree of resistance to molecular diffusion.

[From Dietschy 27.]
Figure 11. Figure 11.

Shift of pH‐absorption curve in rat small intestine. Dashed line, dissociation curve of salicylic acid; solid line, observed absorption curve of salicylic acid. High absorption at pH 10 probably represents absorption in ionized form. [Data from Lucas 74.]
Figure 12. Figure 12.

Dependence of microclimate pH on bulk‐phase pH. Open circles and closed triangles, data from rat proximal jejunum 71, 123. Asterisks, data from guinea pig proximal colon 100. Dotted line, line of identity; solid and dotted lines are calculated by polynomial nonlinear regression by arbitrarily fitting data to a third‐degree polynomial (y = a + b·x + c·x2 + d·x3).
Figure 13. Figure 13.

pH profile along small intestinal villus. Dashed line, bulk‐phase pH. [Data from Daniel et al. 23.]
Figure 14. Figure 14.

Dependence of microclimate pH and clearance in guinea pig proximal colon on bulk‐solution pH. Values are means ± SD. Open circles, microclimate pH measurements; open squares, clearance measurements. [Data from Rechkemmer and von Engelhardt 99 and Rechkemmer et al. 100.]
Figure 15. Figure 15.

Models of carrier‐mediated short‐chain fatty acid (SCFA) transport (A and C) and stimulation of Na+/H+ exchange by hydrogen ion recycling across apical membrane (B). Mechanism of SCFA exit at basolateral membrane is largely unknown.
Figure 16. Figure 16.

Concentration‐absorption relationship of acetate in distal guinea pig colon. Values are means ± SD. [Data from Rechkemmer and von Engelhardt 99.]
Figure 17. Figure 17.

Three‐compartment model. NI, nonionic form; I, ionized form.


Figure 1.

Compartments and barriers in weak electrolyte transport.



Figure 2.

pH dependence of weak electrolyte absorption, partition, and dissociation. Arrow, direction of shift of curve observed in transport experiments.



Figure 3.

pH dependence of weak electrolyte partitioning. Kni, partition coefficient of nonionized form; Ki, partition coefficient of ionized form. Curves calculated according to Equation 14 with pKa = 4.8.



Figure 4.

Shift of pH‐partition curves with pKa. Kni, partition coefficient of nonionized form; Ki, partition coefficient of ionized form.



Figure 5.

pH dependence of n‐octanol/buffer partition coefficients (Kapp) of acetic acid (filled triangles) (G. Rechkemmer, unpublished data) and bromoamiloride (filled circles) (G. Rechkemmer and D. J. Benos, unpublished data). Curves are fitted by nonlinear least‐squares regression analysis by using Equation 14. (Acetic acid data were weighted for the regression analysis.)



Figure 6.

Dependence of apparent partition coefficient on chain length of homologous series of short‐chain fatty acids. Open circles, n‐octanol/water partition; open triangles, hexadecane/water partition; Kapp, apparent partition coefficient. [Data from Stein 129.]



Figure 7.

Dependence of n‐octanol/water partition coefficients and clearance on chain length of a homologous series of short‐chain fatty acids. Clearance was calculated as net flux/mean solute concentration and referred to mucosal dry weight. Asterisk, n‐octanol/water partition coefficients 129; open circles, data from guinea pig proximal colon 99; open squares, data from guinea pig distal colon 99; Kapp, apparent partition coefficient. Lines were calculated by linear regression, slopes ( ± SD): partition coefficients, 1.258 ± 0.076, r = 1.0; proximal colon, 0.148 ± 0.013, r = 0.9925; distal colon, 0.453 ± 0.098, r = 0.9998.



Figure 8.

Nonionic diffusion and parallel channel models of weak electrolyte transport. NI, nonionic form; I, ionized form.

[Adapted from Jackson et al. 54.]


Figure 9.

Schematic representation of unstirred layers as diffusion barriers on both sides of a membrane. Concentration profiles are idealized; in reality they are curvilinear instead of linear as shown. C1 and C2, concentrations in bulk phase; Cm1 and Cm2, concentrations immediately adjacent to membrane; P1, P2, and Pm, permeabilities of unstirred layers and membrane, respectively; d1, d2, and dm, diffusion coefficients of unstirred layers and membrane, respectively.

[Adapted from Macey 83.]


Figure 10.

Diagrammatic representation of uptake of a homologous series of saturated fatty acids under circumstances where there is no diffusion‐barrier resistance (curve A) or where barrier exerts modest (curve B) or high (curve C) degree of resistance to molecular diffusion.

[From Dietschy 27.]


Figure 11.

Shift of pH‐absorption curve in rat small intestine. Dashed line, dissociation curve of salicylic acid; solid line, observed absorption curve of salicylic acid. High absorption at pH 10 probably represents absorption in ionized form. [Data from Lucas 74.]



Figure 12.

Dependence of microclimate pH on bulk‐phase pH. Open circles and closed triangles, data from rat proximal jejunum 71, 123. Asterisks, data from guinea pig proximal colon 100. Dotted line, line of identity; solid and dotted lines are calculated by polynomial nonlinear regression by arbitrarily fitting data to a third‐degree polynomial (y = a + b·x + c·x2 + d·x3).



Figure 13.

pH profile along small intestinal villus. Dashed line, bulk‐phase pH. [Data from Daniel et al. 23.]



Figure 14.

Dependence of microclimate pH and clearance in guinea pig proximal colon on bulk‐solution pH. Values are means ± SD. Open circles, microclimate pH measurements; open squares, clearance measurements. [Data from Rechkemmer and von Engelhardt 99 and Rechkemmer et al. 100.]



Figure 15.

Models of carrier‐mediated short‐chain fatty acid (SCFA) transport (A and C) and stimulation of Na+/H+ exchange by hydrogen ion recycling across apical membrane (B). Mechanism of SCFA exit at basolateral membrane is largely unknown.



Figure 16.

Concentration‐absorption relationship of acetate in distal guinea pig colon. Values are means ± SD. [Data from Rechkemmer and von Engelhardt 99.]



Figure 17.

Three‐compartment model. NI, nonionic form; I, ionized form.

References
 1. Allen, A., and A. Garner. Mucus and bicarbonate secretion in the stomach and their possible role in mucosal protection. Gut 21: 249–262, 1980.
 2. Argenzio, R. A., N. Miller, and W. von Engelhardt Effect of volatile fatty acids on water and ion absorption from the goat colon. Am. J. Physiol. 229: 997–1002, 1975.
 3. Argenzio, R. A., M. Southworth, J. E. Lowe, and C. E. Stevens. Interrelationship of Na, HCO3, and volatile fatty acid transport by equine large intestine. Am. J. Physiol. 233 (Endocrinol. Metab. Gastrointest. Physiol. 2): E469–E478, 1977.
 4. Argenzio, R. A., M. Southworth, and C. E. Stevens. Sites of organic acid production and absorption in the equine gastrointestinal tract. Am. J. Physiol. 226: 1043–1050, 1974.
 5. Argenzio, R. A., and S. C. Whipp. Inter‐relationship of sodium, chloride, bicarbonate and acetate transport by the colon of the pig. J. Physiol. Lond. 295: 365–381, 1979.
 6. Bahari, H. M. M., I. N. Ross, and L. A. Turnberg. Demonstration of a pH gradient across the mucus layer on the surface of human gastric mucosa in vitro. Gut 23: 513–516, 1982.
 7. Barry, P. H., and J. M. Diamond. Effects of unstirred layers on membrane phenomena. Physiol. Rev. 64: 763–872, 1984.
 8. Barry, R. J. C., M. J. Jackson, and D. H. Smyth. Transfer of propionate by rat small intestine in vitro. J. Physiol. Lond. 182: 150–163, 1966.
 9. Barry, R. J. C., and D. H. Smyth. Transfer of short‐chain fatty acids by the intestine. J. Physiol. Lond. 152: 48–66, 1960.
 10. Blair, J. A., M. L. Lucas, and A. M. Matty. Acidification in the rat proximal jejunum. J. Physiol. Lond. 245: 333–350, 1975.
 11. Brasitus, T. A. Lipid dynamics and protein‐lipid interactions in rat colonic epithelial cell basolateral membranes. Biochim. Biophys. Acta 728: 20–30, 1983.
 12. Brasitus, T. A., and P. K. Dudeja. Effect of hypothyroidism on the lipid composition and fluidity of rat colonic apical plasma membranes. Biochim. Biophys. Acta 939: 189–196, 1988.
 13. Brasitus, T. A., and R. S. Keresztes. Isolation and partial characterization of basolateral membranes from rat proximal colonic epithelial cells. Biochim. Biophys. Acta 728: 11–19, 1983.
 14. Bugaut, M. Occurrence, absorption and metabolism of short‐chain fatty acids in the digestive tract of mammals. Comp. Biochem. Physiol. B Comp. Biochem. 86: 439–472, 1987.
 15. Chapelle, S., and M. Gilles‐Baillien. Phospholipids and cholesterol in brush border and basolateral membranes from rat intestinal mucosa. Biochim. Biophys. Acta 753: 269–271, 1983.
 16. Claude, P., and D. A. Goodenough. Fracture faces of zonulae occludentes from “tight” and “leaky” epithelia. J. Cell Biol. 58: 390–400, 1973.
 17. Coe, E. L. Prediction of the relative passive‐transfer rates of short‐chain fatty acids across lipid membranes. Nature Lond. 211: 80–81, 1966.
 18. Collander, R. The permeability of plant protoplasts to non‐electrolytes. Trans. Faraday Soc. 33: 985–990, 1937.
 19. Collander, R., and H. Barlund. Permeabilitatsstudien an Chara ceraceratophylla. II. Die Permeabilitat fur Nichtelektrolyte. Acta Bot. Fenn. 11: 1–114, 1933.
 20. Csaky, T. Z. Intestinal absorption of xenobiotics. In: Pharmacology of Intestinal Permeation, edited by T. Z. Csaky Heidelberg, FRG: Springer‐Verlag, 1984, vol. 70, pt. 2, p. 1–30.
 21. Cummings, J. H. Short chain fatty acids in the human colon. Gut 22: 763–779, 1981.
 22. Cummings, J. H. Colonic absorption: the importance of short chain fatty acids in man. Scand. J. Gastroenterol. Suppl. 93: 89–99, 1984.
 23. Daniel, H., B. Neugebauer, A. Kratz, and G. Rehner. Localization of acid microclimate along intestinal villi of rat jejunum. Am. J. Physiol. 248 (Gastrointest. Liver Physiol. 11): G293–G298, 1985.
 24. Dawson, A. M., C. D. Holdsworth, and J. Webb. Absorption of short chain fatty acids in man. Proc. Soc. Exp. Biol. Med. 117: 97–100, 1964.
 25. Diamond, J. M. A rapid method for determining voltage‐concentration relations across membranes. J. Physiol. Lond. 183: 83–100, 1966.
 26. Diamond, J. M., and E. M. Wright. Biological membranes. The physical basis of ion and non‐electrolyte selectivity. Annu. Rev. Physiol. 31: 581–646, 1969.
 27. Dietschy, J. M. Effect of diffusion barriers on solute uptake into biological systems. In: Microenvironments and Metabolic Compartmentation, edited by P. A. Srere and R. W. Estabrook. New York: Academic, 1978, p. 401–418.
 28. Dietschy, J. M. General principles governing the movement of lipids across biological membranes. In: Disturbances in Lipid and Lipoprotein Metabolism, edited by J. M. Dietschy, A. M. Gotto, Jr., and J. A. Ontko. Bethesda, MD: Am. Physiol. Soc. 1978, p. 1–28.
 29. Dietschy, J. M., V. L. Sallee, and F. A. Wilson. Unstirred water layers and absorption across the intestinal mucosa. Gastroenterology 61: 932–934, 1971.
 30. Engelhardt, W. von, and G. Rechkemmer. Absorption of inorganic ions and short‐chain fatty acids in the colon of mammals. In: Intestinal Transport. Fundamental and Comparative Aspects, edited by M. Gilles‐Baillien and R. Gilles. Berlin: Springer‐Verlag, 1983, p. 26–45.
 31. Engelhardt, W. von, and G. Rechkemmer. The physiological effects of short‐chain fatty in the hind gut. R. Soc. NZ Bull. 20: 149–155, 1983.
 32. Esposito, G. Polarity of intestinal epithelial cells: Permeability of the brush border and basolateral membranes. In: Pharmacology of Intestinal Permeation, edited by T. Z. Csaky Heidelberg, FRG: Springer‐Verlag, 1984, vol. 70, pt. 2, p. 283–308.
 33. Fick, A. Ueber Diffusion. Poggendorff's Annalen 94: 59–86, 1855.
 34. Flemström, G., and E. Kivilaakso. Demonstration of a pH gradient at the luminal surface of rat duodenum in vivo and its dependence on mucosal alkaline secretion. Gastroenterology 84: 787–794, 1983.
 35. Flemström, G., and L. A. Turnberg. Gastroduodenal defence mechanisms. Clin. Gastroenterol. 13: 327–354, 1984.
 36. Frizzell, R. A., and S. G. Schultz. Ionic conductances of extracellular shunt pathway in rabbit ileum. J. Gen. Physiol. 59: 318–346, 1972.
 37. Gutknecht, J., and D. C. Tosteson. Diffusion of weak acids across lipid bilayer membranes: effects of chemical reactions in the unstirred layers. Science Wash. DC 182: 1258–1261, 1973.
 38. Halm, D., R. Schoumacher, and R. Frizzell. Biophysical properties of an apical membrane chloride channel in a secretory epithelial cell line, T84 (Abstract). Federation Proc. 46: 636, 1987.
 39. Hatch, M. Short‐chain fatty acid transport and its effects on ion transport by rabbit cecum. Am. J. Physiol. 253 (Gastrointest. Liver Physiol. 16): G171–G178, 1987.
 40. Henning, S. J., and F. J. R. Hird. Transport of acetate and butyrate in the hind‐gut of rabbits. Biochem. J. 130: 791–796, 1972.
 41. Herschel, D. A., R. A. Argenzio, M. Southworth, and C. E. Stevens. Absorption of volatile fatty acid, Na, and H2O by the colon of the dog. Am. J. Vet. Res. 42: 1118–1124, 1981.
 42. Higuchi, W. I., N. F. H. Ho, J. Y. Park, and I. Komiya. Rate‐limiting steps and factors in drug absorption. In: Drug Absorption: Proceedings of the International Conference on Drug Absorption, edited by L. F. Prescott and W. S. Nimmo. Baltimore, MD: Williams & Wilkins, 1981, p. 35–60.
 43. Hogben, C. A. M., D. J. Tocco, B. B. Brodie, and L. S. Schanker. On the mechanism of intestinal absorption of drugs. J. Pharmacol. Exp. Ther. 125: 275–282, 1959.
 44. Hollander, D., E. M. Gerard, and C. A. R. Boyd. Transport of butyric acid in vascularly perfused anuran small intestine: importance of pH and anion transport. Am. J. Physiol. 250 (Gastrointest. Liver Physiol. 13): G469–G474, 1986.
 45. Högerle, M. L., and D. Winne. Drug absorption by the rat jejunum perfused in situ. Dissociation from the pH‐partition theory and role of microclimate‐pH and unstirred layer. Naunyn‐Schmiedeberg's Arch. Pharmacol. 322: 249–255, 1983.
 46. Ifshin, M. S., K. E. Johnson, and D. C. Eaton. Acid pH and weak acids induce Na‐Cl cotransport in the rabbit urinary bladder. J. Membr. Biol. 76: 151–164, 1983.
 47. Jackson, M. J. Effect of sodium on transport of weak electrolytes across rat jejunum in vitro. J. Physiol. Lond. 348: 417–429, 1984.
 48. Jackson, M. J. Weak electrolyte transport across biological membranes. General principles. In: Physiology of Membrane Disorders, edited by T. E. Andreoli, J. F. Hoffman, D. D. Fanestil, and S. G. Schultz. New York: Plenum, 1986, p. 235–247.
 49. Jackson, M. J. Drug transport across gastrointestinal epithelia. In: Physiology of the Gastrointestinal Tract (2nd ed.), edited by L. R. Johnson New York: Raven, 1987, vol. 2, p. 1597–1621.
 50. Jackson, M. J., and J. A. Dudek. Epithelial transport of weak electrolytes. Federation Proc. 38: 2043–2047, 1979.
 51. Jackson, M. J., and L. M. Kutcher. The three compartment system for transport of weak electrolytes in the small intestine. In: Workshop Conferences Hoechst. Intestinal Permeation, edited by M. Kramer and F. Lauterbach. Amsterdam: Excerpta Med., 1977, vol. 4, p. 65–73.
 52. Jackson, M. J., and C. A. Meaney. Intestinal weak electrolyte transport—models and mechanisms. In: Intestinal Absorption and Secretion, edited by E. Skadhauge and K. Heintze. Lancaster, UK: MTP, 1984, p. 83–91.
 53. Jackson, M. J., and B. N. Morgan. Relations of weak‐electrolyte transport and acid‐base metabolism in rat small intestine in vitro. Am. J. Physiol. 228: 482–487, 1975.
 54. Jackson, M. J., Y. F. Shiau, S. Bane, and M. Fox. Intestinal transport of weak electrolytes. Evidence in favor of a three‐compartment system. J. Gen. Physiol. 63: 187–213, 1974.
 55. Jackson, M. J., C.‐Y. Tai, and J. E. Steane. Weak electrolyte permeation in alimentary epithelia. Am. J. Physiol. 240 (Gastrointest. Liver Physiol. 3): G191–G198, 1981.
 56. Jackson, M. J., A. M. Williamson, W. A. Dombrowski, and D. E. Garner. Intestinal transport of weak electrolytes. Determinants of influx at the luminal surface. J. Gen. Physiol. 71: 301–327, 1978.
 57. Jacobs, M. H. Some aspects of cell permeability to weak electrolytes. Cold Spring Harbor Symp. Quant. Biol. 8: 30–39, 1940.
 58. Jorgensen, K. E., and M. I. Sheikh. Characteristics of uptake of short chain fatty acids by luminal membrane vesicles from rabbit kidney. Biochim. Biophys. Acta 860: 632–640, 1986.
 59. Kitis, G., M. L. Lucas, H. Bishop, A. Sargent, R. E. Schneider, J. A. Blair, and R. N. Allan. Altered jejunal surface pH in coeliac disease: its effect of propranolol and folic acid absorption. Clin. Sci. 63: 373–380, 1982.
 60. Kottra, G., and E. Fromter. Functional properties of the paracellular pathway in some leaky epithelia. J. Exp. Biol. 106: 217–229, 1983.
 61. Kolassa, N., P. Krivanek, and K. Turnheim. Weak electrolyte transfer in the guinea pig jejunum: secretion of trimethoxybenzoic acid. Naunyn‐Schmiedeberg's Arch. Pharmacol. 298: 223–228, 1977.
 62. Kubinyi, H. Lipophilicity and drug activity. In: Progress in Drug Research, edited by E. Jucker Basel: Birkhäuser, 1977, vol. 23, p. 97–198.
 63. Lamers, J. M. J. Some characteristics of monocarboxylate acid transfer across the cell membrane of epithelial cells from rat small intestine. Biochim. Biophys. Acta 413: 265–276, 1975.
 64. Lamers, J. M. J. A monocarboxylate anion carrier in rat small intestinal epithelium. In: Intestinal Permeation, edited by M. Kramer and F. Lauterbach. Amsterdam: Excerpta Med., 1977, p. 64–172.
 65. Lamers, J. M. J., and W. C. Hulsmann. Inhibition of pyruvate transport by fatty acids in isolated cells from rat small intestine. Biochim. Biophys. Acta 394: 31–45, 1975.
 66. Lei, F.‐H., M. L. Lucas, and J. A. Blair. The influence of pH, low sodium ion concentration and methotrexate on the jejunal‐surface pH: a model for folic acid transfer. Biochem. Soc. Trans. 5: 149–152, 1977.
 67. Leng, E. Absorption of inorganic ions and volatile fatty acids in the rabbit caecum. Br. J. Nutr. 40: 509–519, 1978.
 68. Leng‐Peschlow, E., and J. Marty. Absorption of water, electrolytes and volatile fatty acids in the rabbit caecal pouch. J. Comp. Physiol. 133: 205–210, 1979.
 69. Leo, A., C. Hansch, and D. Elkins. Partition coefficients and their uses. Chem. Rev. 71: 525–616, 1971.
 70. Loo, F. D., K. H. Soergel, C. M. Wood, G. L. Gerstner, and J. A. Cunningham. Ileal absorption of short‐chain fatty acids (SCFAs) involves a common rate‐limiting step (Abstract). Gastroenterology 84: 1234, 1983.
 71. Lucas, M. L. The association between acidification and electrogenic events in the rat proximal jejunum. J. Physiol. Lond. 257: 645–662, 1976.
 72. Lucas, M. L. Determination of acid surface pH in vivo in rat proximal jejunum. Gut 24: 734–739, 1983.
 73. Lucas, M. A contribution to analysis of three‐compartment models for intestinal weak electrolyte absorption. Am. J. Physiol. 247 (Gastrointest. Liver Physiol. 10): G463–G467, 1984.
 74. Lucas, M. The surface pH of the intestinal mucosa and its significance in the permeability of organic anions. In: Pharmacology of Intestinal Permeation, edited by T. Z. Csaky Heidelberg, FRG: Springer‐Verlag, 1984, vol. 70, pt. 2, p. 119–163.
 75. Lucas, M. L. Weak‐electrolyte absorption and the acid microclimate. In: Intestinal Absorption and Secretion, edited by E. Skadhauge and K. Heintze. Lancaster, UK: MTP, 1984, p. 39–54.
 76. Lucas, M. L., and J. A. Blair. The magnitude and distribution of the acid microclimate in proximal jejunum and its relation to luminal acidification. Proc. R. Soc. Lond. A Math. Phys. Sci. 200: 27–41, 1978.
 77. Lucas, M. L., J. A. Blair, B. T. Cooper, and W. T. Cooke. Relationship of the acid micro‐climate in rat and human intestine to malabsorption. Biochem. Soc. Trans. 4: 154–156, 1976.
 78. Lucas, M. L., B. T. Cooper, F. H. Lei, I. T. Johnson, G. K. T. Holmes, J. A. Blair, and W. T. Cooke. Acid microclimate in coeliac and Crohn's disease: a model for folate malabsorption. Gut 19: 735–742, 1978.
 79. Lucas, M. L., F. H. Lei, and J. A. Blair. The influence of buffer pH, glucose and sodium ion concentration on the acid microclimate in rat proximal jejunum in vitro. Pfluegers Arch. 385: 137–142, 1980.
 80. Lucas, M. L., and G. T. A. McEwan. The effects of E. coli STa toxin and forskolin on lignocaine absorption from rat jejunum in vivo. J. Physiol. Lond. 403: 46P, 1988.
 81. Lucas, M. L., W. Schneider, F. J. Haberich, and J. A. Blair. Direct measurement by pH‐microelectrode of the pH microclimate in rat proximal jejunum. Proc. R. Soc. Lond. B Biol. Sci. 192: 39–48, 1975.
 82. Luciano, L., E. Reale, G. Rechkemmer, and W. von Engelhardt Structure of zonulae occludentes and the permeability of the epithelium to short‐chain fatty acids in the proximal and the distal colon of guinea pig. J. Membr. Biol. 82: 145–156, 1984.
 83. Lukie, B. E. Studies of mucus permeability. Mod. Probl. Paediatr. 19: 46–53, 1977.
 84. Macey, R. I. Mathematical models of membrane transport processes. In: Physiology of Membrane Disorders (2nd ed.), edited by T. E. Andreoli, J. F. Hoffman, D. D. Fanestil, and S. G. Schultz. New York: Plenum, 1986, p. 111–131.
 85. Marty, J., and M. Vernay. Absorption and metabolism of the volatile fatty acids in the hind‐gut of the rabbit. Br. J. Nutr. 51: 265–277, 1984.
 86. McEwan, G. T. A., H. Daniel, C. Fett, M. N. Burgess, and M. L. Lucas. The effect of Escherichia coli STa enterotoxin and other secretagogues on mucosal surface pH of rat small intestine in vivo. Proc. R. Soc. Lond. B Biol. Sci. 234: 219–237, 1988.
 87. McNeil, N. I., J. H. Cummings, and W. P. T. James. Short chain fatty acid absorption by the human large intestine. Gut 19: 819–822, 1978.
 88. McNeil, N. I., J. H. Cummings, and W. P. T. James. Rectal absorption of short chain fatty acids in the absence of chloride. Gut 20: 400–403, 1979.
 89. McNeil, N. I., and K. L. E. Ling. Large intestinal mucosal surface pH in rat and man. In: Intestinal Absorption and Secretion, edited by E. Skadhauge and K. Heintze. Lancaster, UK: MTP, 1984, p. 103–109.
 90. Meddings, J. B. Lipid permeability of rat jejunum and ileum: correlation with physical properties of the microvillus membrane. Biochim. Biophys. Acta 943: 305–314, 1988.
 91. Naupert, C., and K. Rommel. Absorption of short and medium chain fatty acids in the jejunum of the rat. Z. Klin. Chem. Klin. Biochem. 13: 553–562, 1975.
 92. Nimmerfall, F., and J. Rosenthaler. Significance of the goblet‐cell mucin layer, the outermost luminal barrier to passage through the gut wall. Biochem. Biophys. Res. Commun. 94: 960–966, 1980.
 93. Nord, E. P., S. H. Wright, I. Kippen, and E. M. Wright. Specificity of the Na+‐dependent monocarboxylic acid transport pathway in rabbit renal brush border membranes. J. Membr. Biol. 72: 213–221, 1983.
 94. Orbach, E., and A. Finkelstein. The nonelectrolyte permeability of planar lipid bilayer membranes. J. Gen. Physiol. 75: 427–436, 1980.
 95. Overton, E. Uber die allgemein osmotischen Eigenschaften der Zelle, ihre vermutlichen Ursachen und ihre Bedeutung fur die Physiologie. Vierteljahresschr. Naturforsch. Ges. Zue. 44: 88–114, 1989.
 96. Pappenheimer, J. R., and K. Z. Reiss. Contribution of solvent drag through intercellular junctions to absorption of nutrients by the small intestine of the rat. J. Membr. Biol. 100: 123–136, 1987.
 97. Pedley, T. J. Calculation of unstirred layer thickness in membrane transport experiments: a survey. Q. Rev. Biophys. 16: 115–150, 1983.
 98. Petersen, K.‐U., J. R. Wood, G. Schulze, and K. Heintze. Stimulation of gallbladder fluid and electrolyte absorption by butyrate. J. Membr. Biol. 62: 183–193, 1981.
 99. Rechkemmer, G., K. Ronnau, and W. von Engelhardt Fermentation of polysaccharides and absorption of short chain fatty acids in the mammalian hindgut. Comp. Biochem. Physiol. A Comp. Physiol. 90: 563–568, 1988.
 100. Rechkemmer, G., and W. von Engelhardt Concentration‐ and pH‐dependence of short‐chain fatty acid absorption in the proximal and distal colon of guinea pig (Cavia porcellus). Comp. Biochem. Physiol. A Comp. Physiol. 91: 659–663, 1988.
 101. Rechkemmer, G., M. Wahl, W. Kuschinsky, and W. von Engelhardt pH‐microclimate at the luminal surface of the intestinal mucosal of guinea pig and rat. Pfluegers Arch. 407: 33–40, 1986.
 102. Remesy, C., and C. Demigne. Partition and absorption of volatile fatty acids in the alimentary canal of the rat. Ann. Rech. Vet. 7: 39–55, 1976.
 103. Remesy, C., C. Demigne, and F. Chartier. Origin and utilization of volatile fatty acids in the rat. Reprod. Nutr. Dev. 20: 1339–1349, 1980.
 104. Roediger, W. E. W. The colonic epithelium in ulcerative colitis: an energy‐deficiency disease. Lancet 2: 712–715, 1980.
 105. Roediger, W. E. W. Utilization of nutrients by isolated epithelial cells of the rat colon. Gastroenterology 83: 424–429, 1982.
 106. Roediger, W. E. W., and A. Moore. Effect of short‐chain fatty acid on sodium absorption in isolated human colon perfused through the vascular bed. Dig. Dis. Sci. 26: 100–106, 1981.
 107. Rönnau, K., M. Burmester, and W. von Engelhardt Absorption of ionized short‐chain fatty acids across the colonic epithelium in guinea pig. Pfluegers Arch. 408: R46, 1986.
 108. Rosen, H., A. Leaf, and W. B. Schwartz. Diffusion of weak acids across the toad bladder. Influence of pH on non‐ionic permeability coefficients. J. Gen. Physiol. 48: 379–389, 1964.
 109. Ross, I. N., H. M. M. Bahari, and L. A. Turnberg. The pH gradient across mucus adherent to rat fundic mucosa in vivo and the effect of potential damaging agents. Gastroenterology 81: 713–718, 1981.
 110. Ross, I. N., and L. A. Turnberg. Studies of the ‘mucus‐bicarbonate’ barrier on rat fundic mucosa: the effects of luminal pH and a stable prostaglandin analogue. Gut 24: 1030–1033, 1983.
 111. Ruppin, H., S. Bar‐Meir, K. H. Soergel, C. M. Wood, and M. G. Schmitt, Jr. Absorption of short‐chain fatty acids by the colon. Gastroenterology 78: 1500–1507, 1980.
 112. Rubsamen, K., and W. von Engelhardt Absorption of Na, H ions and short chain fatty acids from the sheep colon. Pfluegers Arch. 391: 141–146, 1981.
 113. Sakaguchi, E., G. Becker, G. Rechkemmer, and W. von Engelhardt Volume, solute concentrations and production of short‐chain fatty acids in the caecum and upper colon of the guinea pig. Z. Tierphysiol. Tierernahr. Futtermittelkd. 54: 276–285, 1985.
 114. Sallee, V. L. Fatty acid and alcohol partitioning with intestinal brush border and erythrocyte membranes. J. Membr. Biol. 43: 187–201, 1978.
 115. Sallee, V. L. Permeation of long‐chain fatty acids and alcohols in rat intestine. Am. J. Physiol. 236 (Endocrinol. Metab. Gastrointest. Physiol. 5): E721–E727, 1979.
 116. Sallee, V. L., and J. M. Dietschy. Determinants of intestinal mucosal uptake of short‐ and medium‐chain fatty acids and alcohols. J. Lipid Res. 14: 475–484, 1973.
 117. Sarosiek, J., A. Slomiany, A. Tagaki, and B. L. Slomiany. Hydrogen ion diffusion in dog gastric mucus glycoprotein: effect of associated lipids and covalently bound fatty acids. Biochem. Biophys. Res. Commun. 118: 523–531, 1984.
 118. Schanker, L. S. Absorption of drugs from the rat colon. J. Pharmacol. Exp. Ther. 126: 283–290, 1959.
 119. Schanker, L. S. On the mechanism of absorption of drugs from the gastrointestinal tract. J. Med. Pharm. Chem. 2: 343–359, 1960.
 120. Schanker, L. S. Mechanisms of drug absorption and distribution. Annu. Rev. Pharmacol. 1: 29–44, 1961.
 121. Schmitt, M. G., K. H. Soergel, and C. M. Wood. Absorption of short chain fatty acids from the human jejunum. Gastroenterology 70: 211–215, 1976.
 122. Schultz, S. G. The role of paracellular pathways in isotonic fluid transport. Yale J. Biol. Med. 50: 99–113, 1977.
 123. Shephard, K. L. The influence of mucus on the diffusion of chloride ions across the oesophagus of the minnow (Phoxinus phoxinus (L.)). J. Physiol. Lond. 346: 449–460, 1984.
 124. Shiau, Y.‐F., P. Fernandez, M. J. Jackson, and S. McMonagle. Mechanisms maintaining a low‐pH microclimate in the intestine. Am. J. Physiol. 248 (Gastrointest. Liver Physiol. 11): G608–G617, 1985.
 125. Shimada, T. Factors affecting the microclimate pH in rat jejunum. J. Physiol. Lond. 392: 113–127, 1987.
 126. Shimada, T., and T. Hoshi. Na+‐dependent elevation of the acidic cell surface pH (microclimate pH) of rat jejunal villus cells induced by cyclic nucleotides and phorbol ester: possible mediators of the regulation of the Na+/H+ antiporter. Biochim. Biophys. Acta 937: 328–334, 1988.
 127. Shore, P. A., B. B. Brodie, and C. A. M. Hogben. The gastric secretion of drugs: a pH‐partition hypothesis. J. Pharmacol. Exp. Ther. 119: 361–369, 1957.
 128. Smithson, K. W., D. B. Millar, L. R. Jacobs, and G. M. Gray. Intestinal diffusion barrier: unstirred layer or membrane surface mucus coat? Science Wash. DC 214: 1241–1244, 1981.
 129. Smyth, D. H., and C. B. Taylor. Intestinal transfer of short‐chain fatty acids in vitro. J. Physiol. Lond. 141: 73–80, 1958.
 130. Stein, W. D. Transport and Diffusion Across Cell Membranes. New York: Academic, 1986.
 131. Stevens, C. E., R. A. Argenzio, and E. T. Clemens. Microbial digestion: rumen versus large intestine. In: Digestive Physiology and Metabolism in Ruminants, edited by Y. Ruckebusch and P. Thivend. Lancaster, UK: MTP, 1980, p. 685–706.
 132. Stevens, C. E., A. Dobson, and J. H. Mammano. A transepithelial pump for weak electrolytes. Am. J. Physiol. 216: 983–987, 1969.
 133. Tai, C.‐Y., and M. J. Jackson. Weak‐acid transport in the small intestine: discrimination in the lamina propria. J. Membr. Biol. 59: 35–43, 1981.
 134. Tai, C.‐Y., and M. J. Jackson. Transport of weak bases across rat gastric mucosa in vivo and in vitro. J. Pharmacol. Exp. Ther. 222: 372–378, 1982.
 135. Taylor, A., J. J. Hess, and R. H. Maffly. The effects of propionate on sodium transport by the toad bladder. Biochim. Biophys. Acta 298: 376–392, 1973.
 136. Thomson, A. B. R. Effect of age on uptake of homologous series of saturated fatty acids into rabbit jejunum. Am. J. Physiol. 239 (Gastrointest. Liver Physiol. 2): G363–G371, 1980.
 137. Thomson, A. B. R. Influence of site and unstirred layers on the rat of uptake of cholesterol and fatty acids into rabbit intestine. J. Lipid Res. 21: 1097–1107, 1980.
 138. Thomson, A. B. R. Influence of sodium on major diffusion barriers to passive intestinal uptake. Am. J. Physiol. 243 (Gastrointest. Liver Physiol. 6): G148–G154, 1982.
 139. Thomson, A. B. R., and J. M. Dietschy. Intestinal kinetic parameters: effects of unstirred layers and transport preparation. Am. J. Physiol. 239 (Gastrointest. Liver Physiol. 2): G372–G377, 1980.
 140. Thomson, A. B. R., C. A. Hotke, D. O. O'Brien, and W. M. Weinstein. Intestinal uptake of fatty acids and cholesterol in four animal species and man: role of unstirred water layer and bile salt micelle. Comp. Biochem. Physiol. A Comp. Physiol. 75: 221–232, 1983.
 141. Thomson, A. B. R., and B. D. O'Brien. Uptake of a homologous series of saturated fatty acids into rabbit intestine using three in vitro techniques. Dig. Dis. Sci. 25: 209–215, 1980.
 142. Titus, E., and G. A. Ahearn. Short‐chain fatty acid transport in the intestine of a herbivorous teleost. J. Exp. Biol. 135: 77–94, 1988.
 143. Turner, N. C., G. P. Martin, and C. Marriott. The influence of native porcine gastric mucus gel on hydrogen ion diffusion: the effect of potentially ulcerogenic agents. J. Pharm. Pharmacol. 37: 776–780, 1985.
 144. Ullrich, K. J., G. Rumrich, S. Klöss, and H. Fasold. Reabsorption of monocarboxylic acids in the proximal tubule of the rat kidney. Pfluegers Arch. 395: 212–231, 1982.
 145. Umesaki, Y., T. Yajima, K. Tohyama, and M. Mutai. Characterization of acetate uptake by the colonic epithelial cells of the rat. Pfluegers Arch. 388: 205–209, 1980.
 146. Vadgama, P., and K. G. M. M. Alberti. The effect of a gastric mucus barrier on the dynamic response of a pH electrode. Experientia Basel 39: 573–576, 1983.
 147. Vernay, M., J. Marty, and J.‐P. Moatti. Absorption of electrolytes and volatile fatty acids in the hind‐gut of the rabbit. Circadian rhythm of hind‐gut electrolytes and plasma aldosterone. Br. J. Nutr. 52: 419–428, 1984.
 148. Walter, A., and J. Gutknecht. Monocarboxylic acid permeation through lipid bilayer membranes. J. Membr. Biol. 77: 255–264, 1984.
 149. Walter, A., and J. Gutknecht. Permeability of small nonelectrolytes through lipid bilayer membranes. J. Membr. Biol. 90: 207–217, 1986.
 150. Walter, A., D. Hastings, and J. Gutknecht. Weak acid permeability through lipid bilayer membranes. J. Gen. Physiol. 79: 917–933, 1982.
 151. Westergaard, H. The passive permeability properties of in vivo perfused rat jejunum. Biochim. Biophys. Acta 900: 129–138, 1987.
 152. Westergaard, H., and J. M. Dietschy. Delineation of the dimensions and permeability characteristics of the two major diffusion barriers to passive mucosal uptake in the rabbit intestine. J. Clin. Invest. 54: 718–732, 1974.
 153. Williams, S. E., and L. A. Turnberg. Retardation of acid diffusion by pig gastric mucus: a potential role in mucosal protection. Gastroenterology 79: 299–304, 1980.
 154. Williams, S. E., and L. A. Turnberg. Demonstration of a pH gradient across mucus adherent to rabbit gastric mucosa: evidence for a “mucus‐bicarbonate’ barrier. Gut 22: 94–96, 1981.
 155. Wilson, F. A., and J. M. Dietschy. The intestinal unstirred layer: its surface area and effect on active transport kinetics. Biochim. Biophys. Acta 363: 112–126, 1974.
 156. Winne, D. The influence of unstirred layers on intestinal absorption. In: Intestinal Permeation, edited by M. Kramer and M. F. Lauterbach. Amsterdam: Excerpta Med., 1977, p. 59–64.
 157. Winne, D. Shift of pH‐absorption curves. J. Pharmacokinet. Biopharm. 5: 53–94, 1977.
 158. Winne, D. Dependence of intestinal absorption in vivo on the unstirred layer. Naunyn‐Schmiedeberg's Arch. Pharmacol. 304: 175–181, 1978.
 159. Winne, D. Deviations of intestinal drug absorption from the pH‐partition theory. Acta Pharm. Technol. 33: 53–59, 1987.
 160. Wolosin, J. M., and H. Ginsburg. The permeation of organic acids through lecithin bilayers: resemblance to diffusion in polymers. Biochim. Biophys. Acta 389: 20–33, 1975.
 161. Wright, E. M., and N. Bindslev. Thermodynamic analysis of nonelectrolyte permeation across toad urinary bladder. J. Membr. Biol. 29: 289–312, 1976.

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Article Title: Transport of Weak Electrolytes
 

How to Cite

Gerhard Rechkemmer. Transport of Weak Electrolytes. Compr Physiol 2011, Supplement 19: Handbook of Physiology, The Gastrointestinal System, Intestinal Absorption and Secretion: 371-388. First published in print 1991. doi: 10.1002/cphy.cp060415