title: On the blood-brain barrier to peptides: [3H]gonadotropin-releasing hormone accumulation by eighteen regions of the rat brain and by anterior pituitary.
abstract: After intracarotid injection of [3H]gonadotropin-releasing hormone ([3H]GnRH) the mean accumulation of radioactivity per unit wet weight of 18 investigated brain samples and the anterior pituitary was 0.38 +/- 0.11% g-1 of the injected tracer dose. This indicates a low but measurable brain uptake of the peptide. The brain uptake of [3H]GnRH in blood-brain barrier (BBB)-protected regions is 5% of that of separately investigated [3H]OH. In BBB-free regions the accumulation of radioactivity was more than 25-fold higher than in BBB-protected regions. The accumulation of [3H]GnRH among regions with BBB varies less than among regions with leaky endothelia. The data presented for [3H]GnRH are similar to those for other peptides so far investigated.
mesh_terms: D000818:Animals; D001812:Blood-Brain Barrier; D001921:Brain / Q000378:metabolism*; D008297:Male; D010455:Peptides / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000378:metabolism*; D010906:Pituitary Hormone-Releasing Hormones / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D014316:Tritium
chemical_list: D010455:Peptides; D010906:Pituitary Hormone-Releasing Hormones; D014316:Tritium