Steroid Hormone Entry into the Brain Requires a Membrane Transporter in Drosophila (Current Biology)

Steroid hormones are thought to freely diffuse across the blood-brain barrier (BBB) due to the predominant `simple diffusion` model of their transport across cell membranes. Okamoto and Yamanaka now provide evidence that the insect steroid hormone ecdysone requires an SLCO superfamily transporter EcI in the BBB to enter the brain in Drosophila.