173054-11-0Relevant articles and documents
Novel Gonadotropin-Releasing Hormone Antagonists: Peptides Incorporating Modified Nω-Cyanoguanidino Moieties
Theobald, Paula,Porter, John,Rivier, Catherine,Corrigan, Anne,Hook, William,et al.
, p. 2395 - 2402 (2007/10/02)
In order to minimize the deleterious effects of histamine release resulting from the administration to rats and humans of some potent gonadotropin-releasing hormone (GnRH) antagonists, various arginine residues were replaced with the less basic Nω-cyano-Nω'-alkyl- or -arylhomoarginine, -arginine, or -p-aminophenylalanine and Nω-triazolyllysine, -ornithine or -p-aminophenylalanine residues in active analogues.These novel analogues were synthesized on a solid-phase support via a two-step modification of the Nω-NH2 of lysine, ornithine, or p-aminophenylalanineresidues in otherwise protected resin bound peptides.Most analogues were tested in the rat antiovulatory assay (AOA) and three in vitro assays: a pituitary cell culture assay, a binding assay to pituitary cell membranes, and a histamine release assay.Introduction of the cyanoguanidino and Nω-triazolyl moieties into GnRH analogues yielded several water-soluble antagonists which showed a desirable therapeutic ratio (low histamine release activity to high in vivo potency).Among them, "Azaline" (10, 1,DCpa2,DPal3,Lys5(atz),DLys6(atz),ILys8,DAla10>GnRH), inhibited ovulation in the rat by 90percent at 2 μg/rat with an ED50 in the in vitro histamine release assay comparable to that of GnRH itself.
