title: Characterization and subcellular localization of GnRH analog binding in rat brain.
abstract: The binding of a degradation-resistant analog of gonadotropin-releasing hormone, [D-Phe6]GnRH, to rat brain crude particulate preparation was studied. The binding of this analog at 0 degrees C was saturable and Scatchard analysis revealed the presence of 2 binding sites: one with KD = 1.39 x 10(-7) M and Bmax = 265 pmole/mg protein, and another of lower affinity but higher capacity with KD = 5.58 X 10(-6) M and Bmax = 1734 pmoles/mg protein. The binding at 0 degrees C was substantially higher than that obtained at 37 degrees C, due to binding site-inactivation processes occurring at 37 degrees C. The binding sites exhibited a considerable degree of specificity for GnRH as unrelated peptides (with the exception of ACTH) display a much weaker affinity than GnRH and GnRH analogs. Subcellular fractionation demonstrated that most of the binding was associated with the mitochondrial fraction.
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000378:metabolism; D007700:Kinetics; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013696:Temperature
chemical_list: D007987:Gonadotropin-Releasing Hormone; C034458:LHRH, Phe(6)-; D000324:Adrenocorticotropic Hormone