These findings support the use of sulfated and/or glucuronidated BS as biomarkers of the genetic or chemical inhibition of OATP1B1 and OATP1B3 [45,48,49] and, given the increased production of sulfated BA/BS in cholestasis [50], underline the importance of OATP1B1 and OATP1B3 in BA/BS clearance under cholestatic conditions. Here, SLCO1B1 is linked to cholestasis.