Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1976 Mar;256(1):197–208. doi: 10.1113/jphysiol.1976.sp011320

Aspects of intestinal folate transport in the rat.

J A Blair, I T Johnson, A J Matty
PMCID: PMC1309300  PMID: 933030

Abstract

1. In vitro preparations of rat jejunum were used to study the metabolic dependence, the structural specificity, and the pH sensitivity of the folic acid absorption process. 2. The presence of 2:4 dinitrophenol, and the absence of oxygen, in the muscosal bathing medium both led to a decrease in the tissue accumulation and serosal transfer of folic acid by everted sacs. 3. 10-formylfolic acid, present in the mucosal medium at a molar ratio of 10:1 with labelled folic acid, appears to compete for tissue accumulation sites but has no significant effect on serosal transfer. 4. The efflux of folic acid from pre-loaded jejunal sacs is stimulated by the presence in the mucosal medium of the folic acid and related compounds. Pteroyl-L-glutamic acid, 10-formylfolic acid and methotrexate elicit a significant increase in the efflux rate; pteroyl-D-glutamic acid was significantly less effective and pteroic acid had no effect. 5. The uptake of folic acid by isolated jejunal cells prepared by enzymic disaggregation of the mucosa, was found to be influenced by the pH of the bathing medium, uptake being enhanced at a pH of between 5 and 6. 6. It is concluded that the effect of metabolic inhibitors and acid pH conditions on the uptake of folic acid in vitro is consistent with a passive absorption mechanism, influenced in intact preparations and in vivo by the jejunal pH microclimate. However the occurrence of competitive inhibition and stimulated efflux may indicate the existence of a structurally specific accumulation process at some site, or sites, within the mucosa.

Full text

PDF
197

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BUTTERWORTH C. E., Jr, SANTINI R., Jr, FROMMEYER W. B., Jr THE PTEROYLGLUTAMATE COMPONENTS OF AMERICAN DIETS AS DETERMINED BY CHROMATOGRAPHIC FRACTIONATION. J Clin Invest. 1963 Dec;42:1929–1939. doi: 10.1172/JCI104879. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Beavon J. R., Blair J. A. The metabolism of some folates in the rat. Br J Nutr. 1975 May;33(3):299–308. doi: 10.1079/bjn19750035. [DOI] [PubMed] [Google Scholar]
  3. Blair J. A., Johnson I. T., Matty A. J. Absorption of folic acid by everted segments of rat jejunum. J Physiol. 1974 Feb;236(3):653–661. doi: 10.1113/jphysiol.1974.sp010458. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Blair J. A., Lucas M. L., Matty A. J. Acidification in the rat proximal jejunum. J Physiol. 1975 Feb;245(2):333–350. doi: 10.1113/jphysiol.1975.sp010849. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Blair J. A., Matty A. J. Acid microclimate in intestinal absorption. Clin Gastroenterol. 1974 Jan;3(1):183–197. [PubMed] [Google Scholar]
  6. Blair J. A., Matty A. J., Razzaque A. Uptake of 5-methyltetrahydrofolic acid by the rat jejunum. J Physiol. 1975 Sep;250(2):221–230. doi: 10.1113/jphysiol.1975.sp011050. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Elsborg L. Folic acid: a new approach to the mechanism of its intestinal absorption. Dan Med Bull. 1974 Mar;21(1):1–11. [PubMed] [Google Scholar]
  8. Hakala M. T. On the nature of permeability of sarcoma-180 cells to amethopterin in vitro. Biochim Biophys Acta. 1965 May 25;102(1):210–225. doi: 10.1016/0926-6585(65)90214-1. [DOI] [PubMed] [Google Scholar]
  9. Hakala M. T. On the role of drug penetration in amethopterin resistance of Sarcoma-180 cells in vitro. Biochim Biophys Acta. 1965 May 25;102(1):198–209. doi: 10.1016/0926-6585(65)90213-x. [DOI] [PubMed] [Google Scholar]
  10. Kesavan V., Noronha J. M. Effect of x-radiation on the absorption of naturally-occurring folates. Int J Radiat Biol Relat Stud Phys Chem Med. 1971;19(3):205–214. doi: 10.1080/09553007114550311. [DOI] [PubMed] [Google Scholar]
  11. Kimmich G. A. Preparation and properties of mucosl epithelial cells isolated frmsmall intestine of the chicken. Biochemistry. 1970 Sep 15;9(19):3659–3668. doi: 10.1021/bi00821a003. [DOI] [PubMed] [Google Scholar]
  12. Leslie G. I., Rowe P. B. Folate binding by the brush border membrane proteins of small intestinal epithelial cells. Biochemistry. 1972 Apr 25;11(9):1696–1703. doi: 10.1021/bi00759a026. [DOI] [PubMed] [Google Scholar]
  13. Lucas M. L., Schneider W., Haberich F. J., Blair J. A. Direct measurement by pH-microelectrode of the pH microclimate in rat proximal jejunum. Proc R Soc Lond B Biol Sci. 1975 Dec 31;192(1106):39–48. doi: 10.1098/rspb.1975.0150. [DOI] [PubMed] [Google Scholar]
  14. Olinger E. J., Bertino J. R., Binder H. J. Intestinal folate absorption. II. Conversion and retention of pteroylmonoglutamate by jejunum. J Clin Invest. 1973 Sep;52(9):2138–2145. doi: 10.1172/JCI107398. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Perris A. D. Isolation of the epithelial cells of the rat small intestine. Can J Biochem. 1966 Jun;44(6):687–693. doi: 10.1139/o66-086. [DOI] [PubMed] [Google Scholar]
  16. Smith M. E., Matty A. J., Blair J. A. The transport of pteroylglutamic acid across the small intestine of the rat. Biochim Biophys Acta. 1970;219(1):37–46. doi: 10.1016/0005-2736(70)90059-3. [DOI] [PubMed] [Google Scholar]
  17. Smith M. E. The uptake of pteroylglutamic acid by the rat jejunum. Biochim Biophys Acta. 1973 Feb 27;298(1):124–129. doi: 10.1016/0005-2736(73)90017-5. [DOI] [PubMed] [Google Scholar]
  18. TURNER J. B., HUGHES D. E. The absorption of some B-group vitamins by surviving rat intestine preparations. Q J Exp Physiol Cogn Med Sci. 1962 Apr;47:107–133. doi: 10.1113/expphysiol.1962.sp001582. [DOI] [PubMed] [Google Scholar]
  19. Yoshino T. The clinical and experimental studies on the metabolism of folic acid using tritiated folic acid. II. The experimental studies on the absorption site and mechanism of tritiated folic acid in rats. J Vitaminol (Kyoto) 1968 Mar 10;14(1):35–48. doi: 10.5925/jnsv1954.14.35. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES