Studies performed on a variety of species (pigs, sheep, rabbits, rats) indicate the existence of a local transfer system of substances between blood vessels located at the base of the cranium (the cavernous sinus - carotid artery vascular complex). This local transfer allows for some hormones synthesized in the brain and hypophysis, as well as biologically active substances absorbed from the nasal mucosa, and drained to the cavernous sinus to reach the brain vasculature in a concentration locally higher than that measured in systemic circulation. The present paper gives an overview of: 1. the major anatomical structure engaged in the transfer, 2. experimental evidence for substance transfer in the vascular complex, 3. factors affecting the transfer and 4. possible physiological importance.