L-type amino acid transporters in two intestinal epithelial cell lines function as exchangers with neutral amino acids

• Type: Article in International Scientific Journal
• Date: 2002

Authors

Sonia Fraga (Author) Other; Maria Paula Serrão (Author) FMUP; soares-da-silva, p (Author) FMUP

Journal

Title: Journal of Nutrition

Vol. 132

Pages: 733-738

ISSN: 0022-3166

Publisher: American Society for Nutritional Sciences

Indexing

ISI Web of Knowledge - 25 Citations

Scopus - 27 Citations

Other information

Authenticus ID: P-000-PX5

Abstract (EN): The present study examined the functional characteristics of the inward [C-14]-L-leucine transporter in two intestinal epithelial cell lines (human Caco-2 and rat IEC-6). The uptake of [C-14]-L-leucine was largely promoted through an energy-dependent and sodium-insensitive transporter, although a minor component of [C-14]-L-leucine uptake (similar to15%) required extracellular sodium. [C-14]-L-leucine uptake was insensitive to N-(methylamino)-isobutyric acid, but competitively inhibited by 2-aminobicyclo(2,2,1)-heptane-2-carboxylic acid (BCH). Both L- and D-neutral amino acids, but not acidic and basic amino acids, markedly inhibited [C-14]-L-leucine accumulation. The efflux of [C-14]-L-leucine was markedly increased (P < 0.05) by L-leucine and BCH, but not by L-arginine. In IEC-6 cells, but not in Caco-2 cells, the uptake of [C-14]-L-leucine at acidic pH (5.0 and 5.4) was greater (P < 0.05) than at pH 7.4. In conclusion, it is likely that system B-0 might be responsible for the sodium-dependent uptake of L-leucine in Caco-2 and IEC-6 cells, whereas sodium-independent uptake of L-leucine may include system LAT1, whose activation results in transstimulation of L-leucine outward transfer.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6