title: Antagonists of the luteinizing hormone releasing hormone (LHRH) with emphasis on the TRP7 of the salmon and chicken II LHRH's.
abstract: The sequences of four naturally occurring luteinizing hormone releasing hormones (LHRH's) differ only in positions 5, 7 and 8. Salmon and chicken II LHRH's have Trp7; porcine/ovine (P/O) and chicken I LHRH's have Leu7. The receptor for P/O LHRH might effectively bind certain antagonists with Trp7. Thirteen antagonists having Trp7 and eight antagonists with other substitutions in position 7 were synthesized. One of the thirteen antagonists with the natural Trp7, [N-Ac-D-2-Nal1,D-pClPhe2,D-3-Pal3,D-Arg6,Trp7,D- Ala10]-LHRH, not only maintained activity, but had increased potency (ca. 58%; 90% antiovulatory activity/250 ng; rats) in comparison with the companion analog with the natural Leu7 of P/O LHRH. The other twelve Trp7-antagonists had lower potency.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000138:chemical synthesis / Q000494:pharmacology; D007202:Indicators and Reagents; D010060:Ovulation / Q000187:drug effects; D012474:Salmon; D012756:Sheep; D013329:Structure-Activity Relationship; D013552:Swine
chemical_list: D007202:Indicators and Reagents; D007987:Gonadotropin-Releasing Hormone; C042948:LHRH, Trp(7)-