Omeprazole decreased MgA→B transport and PMg in both a dose- and time-dependent manner.
As demonstrated in Figure 1, the MgA→B transport vs Mg2+ concentration plots of Caco-2 monolayers were curvilinear similar to that reported in humans[5]. After 14 d in
the omeprazole-treated groups, MgA→B transport was inhibited
when compared with its corresponding untreated
group (Figures 1A-F). The level of inhibition progressively
increased with higher concentrations of omeprazole.
Omeprazole selectively decreased non-saturable MgA→B
transport, but not the saturated component, as clearly
demonstrated by the lower rate constant for non-saturable
MgA→B transport (Table 1). For 21 d omeprazoletreated
groups, the results were similar to those of the 14
d omeprazole-treatment (Figure 1G-L, Table 1). When the
same omeprazole concentration was considered, 21 d-treated
groups showed a significantly lower MgA→B transport
than the 14 d-treated groups (Figure 1, Table 1). Therefore,
omeprazole decreased MgA→B transport in a dose- and
time-dependent manner. According to the MgA→B transport,
omeprazole also decreased the apical to basolateral
PMg in a dose- and time-dependent mechanism (Figure 2).
Moreover, omeprazole significantly increased TER, but not
PD or ISC, of Caco-2 monolayers (Table 2), indicating the
lower paracellular permeability to ion transport.