Abstract: Novel pentapeptides having the following amino acid sequenceX--Y--Z--E--G--J--Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; Z is selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; E is selected from a group consisting of glycine, alanine, valine, leucine, methionine, and isoleucine; J is selected from a group consisting of glycine, alanine, D-alanine, valine, D-valine, leucine, D-leucine, isoleucine, D-isoleucine, proline, D-proline, hydroxyproline, D-hydroxyproline, serine, D-serine, threonine, D-threonine, cysteine, D-cysteine, methionine, and D-methionine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof.

Abstract: Novel pentapeptides having the following amino acid sequenceX-Y-Z-E-G-J-Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y and G are independently selected from a group consisting of tyrosine, trytophan, and phenlalanine; Z and J are independently selected from a group consisting of D-tyrosine, D-tryptophan, an D-phenylalanine; E is selected from a group consisting of glycine, alanine, valine, leucine, isoleucine, proline, hydroxyproline, serine, threonine, cysteine, methionine, aspartic acid, glutamic acid, asparagine, glutamine, and histidine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel pentapeptides having the following amino acid sequenceX-Y-Z-E-G-J-Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y and E are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; Z and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; J is selected from a group consisting of glycine, alanine, valine, leucine, isoleucine, proline, hydroxyproline, serine, threonine, cysteine, methionine, aspartic acid, glutamic acid, asparagine, glutamine, arginine, and lysine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel pentapeptides having the following amino acid sequenceX--Y--Z--E--G--J--Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y is selected from a group consisting of D-lysine and D-arginine; Z and J are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; E and G are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel tetrapeptides having the following amino acid sequenceX--Y--Z--E--G--Jwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; Y and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; Z and E are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; and J is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: Novel pentapeptides having the following amino acid sequenceX--Y--Z--E--G--J--Lwherein X is selected from a group consisting of --NH.sub.2, --NHCH.sub.3, and --N(CH.sub.3).sub.2 ; wherein Y and G are independently selected from a group consisting of tyrosine, tryptophan, and phenylalanine; Z is selected from a group consisting of glycine, alanine, valine, leucine, isoleucine, proline, hydroxyproline, serine, threonine, cysteine, and methionine; E and J are independently selected from a group consisting of D-tyrosine, D-tryptophan, and D-phenylalanine; and L is a C-terminal functional group selected from a group consisting of amide, amide lower alkyl, amide di(lower alkyl), lower alkoxy, hydroxy, and carboxy and the lower ester derivatives thereof; and the pharmaceutically acceptable salts thereof. These peptides act directly on the pituitary to release growth hormone therefrom.

Abstract: A method for isolating D and L amino acids from a racemic mixture of the formula(DL)--H.sub.2 N--CHX--COOY,and salts thereof, wherein X denotes an amino acid side chain and derivatives thereof and Y denotes a suitable alkyl group. The racemic mixture is contacted with water to form an aqueous solution. This aqueous solution is then contacted with an esterase to thereby obtain a solution comprising the resolved amino acids(L)--H.sub.2 N--CHX--COOH and(D)--H.sub.2 N--CHX--COOY.The N-terminus of the resolved (L) and (D) amino acids present in this solution are protected with an N-protecting group R to thereby obtain a solution comprising(L)--R--NH--CHX--COOH and(D)--R--NH--CHX--COOY.The isolation of (L)--R--NH--CHX--COOH from (D)--R--NH--CHX--COOY is achieved in high yields by an acid-base extraction.