The transport mechanism of monocarboxylate transporter on spinosin in Caco-2 cells.
OBJECTIVE
The aim of this study was to determine the uptake mechanism of spinosin (SPI) by the monocarboxylic acid transporters (MCTs) in Caco-2 cells.


METHODS
The Caco-2 cells were pretreated with various monocarboxylic acids, and the uptake of spinosin from Caco-2 cells was measured by High Performance Liquid Chromatography (HPLC).


RESULTS
Preloading of various monocarboxylic acids enhanced the uptake of SPI, especially salicylic acid (a substrate of MCTs) had a 23.4 times increase in SPI uptake, indicating that the monocarboxylic acid transporters had an efflux effect on SPI uptake and salicylic acid had a strong inhibition on SPI efflux in Caco-2 cells. At the same time, the uptake of SPI through Caco-2 cells was Na(+)- and temperature-dependent, pretreatment without Na(+) significantly increased the uptake of SPI by 1.85 times and incubated at low temperature (4 °C) SPI uptake increased 20% than that of 37 °C. Furthermore, SPI was transported mainly via a carrier-mediated transport: [Vmax = 5.364 μg/mg protein, Km = 657.0 μg/mL].


CONCLUSIONS
The uptake of spinosin (SPI) in Caco-2 cells was mainly regulated by the monocarboxylic acid transporters along with Salicylic acid.
The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou, China; International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, China.
Xiang Le
XL
Meng
Discipline of Pharmacy, Henan University of Traditional ​ Chinese Medicine, Zhengzhou, China.
Yan Li
YL
Guo
Discipline of Pharmacy, Henan University of Traditional ​ Chinese Medicine, Zhengzhou, China.
Hai
H
Ying Huang
Caco-2 cells; Monocarboxylic acid transporters (MCTs); Salicylic acid; Spinosin (SPI)