Furthermore, if an agent is able to penetrate one or both of these membranes, it is often subject to rapid
efflux out of the cell by numerous broadly acting efflux pumps - rendering the agent ineffective.
For example, up - regulated influx transporters (OCT3 and OCTN1) localized at the apical membranes
of Sertoli
cells could mediate the transport
of the drug compound 9 from the lumen into the basolateral compartment
of Sertoli
cells, where the up - regulated
efflux transporters (ABCB1 / p - glycoprotein, ABCB8, ABCB9, ABCC5, and ABCC10) could then transport the drug
out of Sertoli
cells against a concentration gradient, resulting in enhanced efficiency
of recovery upon cessation
of treatment.