“…As the best-studied ATP-binding cassette transporter, P-glycoprotein (P-gp) can expel various drugs from cells, resulting in multidrug resistance, and is likely to play a critical role in the uptake and absorption of substrate drugs (Dreisbach 2009;Naud et al, 2012). The intestinal absorption of some iridoid glycosides, like geniposide, catalpol and loganin, is enhanced by the inhibition of the intestinal P-gp activity (Chula et al, 2012;Feng et al, 2013;Li et al, 2008). Therefore, iridoids glycoside might be a substrate for intestinal P-gp and the decrease in intestinal P-gp could explain the increased bioavailability of catalpol in CKD rats (Kozlowska-Rup et al, 2014).…”