Uptake of manganese from manganese-lysine complex in the primary rat intestinal epithelial cells

This study was conducted to compare the differences of the uptake of Mn from Mn-lysine complex (MnLys) and MnSO₄ and to determine the potential mechanisms of the uptake of Mn from MnLys. We first established the primary rat intestinal epithelial cell culture model and used it to determine the uptake of Mn from different Mn sources. The MnLys increased (p < 0.001) Mn uptake when compared to MnSO₄ . The uptake of Mn decreased (p < 0.05) with added Fe concentration increasing in the medium regardless of Mn source. The MnLys decreased (p < 0.01) Mn²⁺ efflux transporter ferroportin 1 (FPN1) mRNA level, but did not influence (p > 0.06) Mn²⁺ influx transporter DMT1 mRNA expression when compared to MnSO₄ . The results above indicated that the increase of Mn accumulation for MnLys at least partly was due to the decrease of Mn efflux by reduced FPN1 expression. The N-ethylmaleimide, as an l-lysine transport system y⁺ inhibitor, decreased (p < 0.001) the uptake of Mn from MnLys, but did not affect (p > 0.10) the uptake of Mn from MnSO₄ . The cycloheximide, as an l-lysine transport system b^0,+ activator, increased (p < 0.001) the uptake of Mn from MnLys, whereas also did not influence the uptake of Mn from MnSO₄ . The MnLys increased (p < 0.01) the system y⁺ member cationic amino acid transporter (CAT) 1, and system b^0,+ components rBAT and b^0,+ AT mRNA expression when compared to MnSO₄ . These results suggested that the uptake of Mn from MnLys complex might be transported by CAT1 and system b^0,+ , which was different from ionized Mn²⁺ uptake pathway. In conclusion, the uptake of MnLys complex not only might be absorbed as Mn²⁺ , but also appeared to be transported through CAT1 and system b^0,+ in the primary rat intestinal epithelial cells.