title: Biotin transport through the blood-brain barrier.
abstract: The unidirectional influx of biotin across cerebral capillaries, the anatomical locus of the blood-brain barrier, was measured with an in situ rat brain perfusion technique employing [3H]biotin. Biotin was transported across the blood-brain barrier by a saturable system with a one-half saturation concentration of approximately 100 microM. The permeability-surface area products were 10(-4) s-1 with a biotin concentration of 0.02 microM in the perfusate. Probenecid, pantothenic acid, and nonanoic acid but not biocytin or biotin methylester (all 250 microM) inhibited biotin transfer through the blood-brain barrier. The isolated rabbit choroid plexus was unable to concentrate [3H]biotin from medium containing 1 nM [3H]biotin. These observations provide evidence that: biotin is transported through the blood-brain barrier by a saturable transport system that depends on a free carboxylic acid group, and the choroid plexus is probably not involved in the transfer of biotin between blood and cerebrospinal fluid.
mesh_terms: D000818:Animals; D001710:Biotin / Q000378:metabolism*; D001812:Blood-Brain Barrier; D002199:Capillary Permeability; D002560:Cerebrovascular Circulation; D008239:Lysine / Q000031:analogs & derivatives / Q000494:pharmacology; D008433:Mathematics; D010205:Pantothenic Acid / Q000494:pharmacology; D010477:Perfusion; D011339:Probenecid / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D010205:Pantothenic Acid; D001710:Biotin; C013411:biocytin; D008239:Lysine; D011339:Probenecid