LHRH antagonists

Abstract

Disclosed herein are analogues of the luteinizing hormone-releasing hormone (LH-RH), which are potent antagonists of LH-RH. These peptides inhibit the release of gonadotropins from the pituitary in mammals, including humans and possess antitumor activity. Formula I represents peptides which are within the scope of this invention: X--R.sup.1 --R.sup.2 --R.sup.3 --Ser--R.sup.5 --R.sup.6 (AY.sub.2)--Leu--Arg--Pro--D--Ala--NH.sub.2 I and the pharmaceutically acceptable salts thereof, wherein R.sup.1 is D-Phe, D-Phe(4Cl), D-Nal(1) or D-Nal(2), R.sup.2 is D-Phe or D-Phe(4HI), R.sup.3 is D-Trp, D-Phe, D-Phe(4HI), D-Nal(1), D-Nal(2) or D-Pal(3), R.sup.5 is Tyr or Arg, R.sup.6 is D-Lys or D-Orn, HI is fluoro, chloro or bromo X is a lower alkanoyl group of 2-5 carbon atoms, A is a diaminoacyl residue having the formula ##STR1## where m is 0 or 1, n is 0 or 1, Y is Y.sup.1 or Y.sup.2, wherein Y.sup.1 is an acyl group derived from straight or branched chain aliphatic, alicyclic carboxylic acids having from 3 to 12 carbon atoms or aromatic carboxylic acid of 6 or 10 ring carbon atoms, Y.sup.2 is carbamoyl or alkyl-substituted carbamoyl group having the formula H--(CH.sub.2).sub.n --NH--CO-- III where n is 0-3.

Dependencies are inferred from the claim text.