Modulating the Blood–Testis Barrier Towards Increasing Drug Delivery

Testicular cells produce several biologically active peptides that exert their downstream effects by activating distinct signaling proteins. These biomolecules are now known to support spermatogenesis and effectively enhance paracellular and transcellular diffusion of drugs (e.g., adjudin) across the blood–testis barrier (BTB). We briefly discuss the biomolecules that maintain the BTB: these provide new insights into how the BTB can be modulated to allow therapeutic drugs, including male contraceptives, to be transported across the BTB and more generally across blood–tissue barriers. Information gleaned by studying the BTB, as well as other blood–tissue barriers, augments our understanding of blood–tissue barriers and provides new insights into how drugs can be delivered to organs that are effectively protected by tissue barriers.