title: Hormonal interactions with benzodiazepine binding sites in vitro.
abstract: Prostaglandin A1 and hormones like corticosteroids and DL-Thyroxin (T4) inhibit binding of [3H]RO 5-4864 and [3H] Clonazepam to their respective binding sites with inhibition constants in the low micromolar range. The corticosteroid Cortisone inhibits [3H] RO 5-4864, but not [3H] Clonazepam binding in a competitive manner with an inhibition constant of 4.3 +/- 0.7 microM, Prostaglandin A1 inhibits [3H] Clonazepam, but not [3H] RO 5-4864 binding in a competitive manner with an inhibition constant of 6 +/- 1.2 microM and DL-Thyroxin (T4) inhibits both [3H] RO 5-4864 and [3H] Clonazepam binding with inhibition constants of 12.1 +/- 2.2 and 1.6 +/- 0.4 microM respectively. While the inhibition of [3H] RO 5-4864 binding by DL-Thyroxin (T4) is competitive, the inhibition of [3H] Clonazepam binding is of the mixed type as indicated by Scatchard Plot.
mesh_terms: D000305:Adrenal Cortex Hormones / Q000378:metabolism; D000818:Animals; D001570:Benzodiazepinones / Q000378:metabolism; D001667:Binding, Competitive; D002998:Clonazepam / Q000378:metabolism; D006728:Hormones / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D011453:Prostaglandins / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000378:metabolism*; D013974:Thyroxine / Q000378:metabolism
chemical_list: D000305:Adrenal Cortex Hormones; D001570:Benzodiazepinones; D006728:Hormones; D011453:Prostaglandins; D011963:Receptors, GABA-A; C028513:4'-chlorodiazepam; D002998:Clonazepam; D013974:Thyroxine