Transport of thiamine in human intestine: mechanism and regulation in intestinal epithelial cell model Caco-2
- 1 October 1999
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Cell Physiology
- Vol. 277 (4) , C645-C651
- https://doi.org/10.1152/ajpcell.1999.277.4.c645
Abstract
The present study examined the intestinal uptake of thiamine (vitamin B1) using the human-derived intestinal epithelial cells Caco-2 as an in vitro model system. Thiamine uptake was found to be 1) temperature and energy dependent and occurred with minimal metabolic alteration; 2) pH sensitive;3) Na+ independent;4) saturable as a function of concentration with an apparent Michaelis-Menten constant of 3.18 ± 0.56 μM and maximal velocity of 13.37 ± 0.94 pmol ⋅ mg protein−1 ⋅ 3 min−1;5) inhibited by the thiamine structural analogs amprolium and oxythiamine, but not by unrelated organic cations tetraethylammonium,N-methylnicotinamide, and choline; and6) inhibited in a competitive manner by amiloride with an inhibition constant of 0.2 mM. The role of specific protein kinase-mediated pathways in the regulation of thiamine uptake by Caco-2 cells was also examined using specific modulators of these pathways. The results showed possible involvement of a Ca2+/calmodulin (CaM)-mediated pathway in the regulation of thiamine uptake. No role for protein kinase C- and protein tyrosine kinase-mediated pathways in the regulation of thiamine uptake was evident. These results demonstrate the involvement of a carrier-mediated system for thiamine uptake by Caco-2 intestinal epithelial cells. This system is Na+ independent and is different from the transport systems of organic cations. Furthermore, a CaM-mediated pathway appears to play a role in regulating thiamine uptake in these cells.Keywords
This publication has 29 references indexed in Scilit:
- A Protein-tyrosine Kinase-regulated, pH-dependent, Carrier-mediated Uptake System for Folate in Human Normal Colonic Epithelial Cell Line NCM460Journal of Biological Chemistry, 1997
- Alcoholic cognitive deterioration and nutritional deficienciesActa Neurologica Scandinavica, 1994
- Thiamin status of the elderly: dietary intake and thiamin pyrophosphate response.Journal of the American College of Nutrition, 1994
- Human intestinal cell line Caco-2: a useful model for studying cellular and molecular regulation of biotin uptakeBiochimica et Biophysica Acta (BBA) - Biomembranes, 1994
- Proline uptake by monolayers of human intestinal absorptive (Caco-2) cells in vitroBiochimica et Biophysica Acta (BBA) - Biomembranes, 1992
- Transport of bile acids in a human intestinal epithelial cell line, Caco-2Biochimica et Biophysica Acta (BBA) - General Subjects, 1990
- Thiamine transport in the brush border membrane vesicles of the guinea-pig jejunumBiochimica et Biophysica Acta (BBA) - Biomembranes, 1981
- Carrier-mediated transport of thiamine in baker's yeastBiochimica et Biophysica Acta (BBA) - Biomembranes, 1973
- The Na+-dependence of thiamin intestinal transportLife Sciences, 1971
- Peripheral Neuropathy of the Alcoholic: I, Aetiological Role of Aneurin and Other B-complex VitaminsBMJ, 1964