Psychopharmacological peptides

A pharmaceutical composition effective for treating schizophrenia, comprising:

• (A) a pharmaceutically effective amount of a compound of the formula:
• A.sub.1 -A.sub.2 -L-Phe-X-L-Thr-L-Ser-R.sub.1 -Y-L-Ser-R.sub.2 -L-Thr-L-Pro-L-Leu-Val-L-Thr-B
• wherein:
• (1) A.sub.1 and A.sub.2 each represent an L-amino-acid residue of the formula H.sub.2 N-ALK-CO-, wherein ALK is an alkylidene group with 1 to 6 carbon atoms;
• (2) X is an amino-acid residue selected from the group consisting of L-Met, L-Met(O), L-Met(O.sub.2), and L-Leu;
• (3) R.sub.1 and R.sub.2 each represent one of the amino-acid residues selected from the group consisting of L-Glu and L-Gln;
• (4) Y represents an amino-acid residue selected from the group consisting of L-Lys and D-Lys;
• and
• (5) B represents one of the amino-acid- or peptide-moieties selected from L-Leu-OH, D-Leu-OH, L-Leu-L-Phe-OH, L-Leu-L-Phe-L-Lys-OH, L-Leu-L-Phe-D-Lys-OH, L-leucinol and L-MeLeu-OH;
• and functional derivatives of said compound selected from the group consisting of pharmaceutically acceptable acid addition salts, pharmaceutically acceptable metal salts, aliphatic esters containing up to about eighteen carbon atoms unsubstituted amides, amides substituted with alkyl group (s) having up to about six carbon atoms, N-acyl derivatives wherein the aliphatic carboxylic acid group has from up to about six carbon atoms, and pharmaceutically acceptable metal complexes, and
• (B) a pharmaceutically effective carrier therefor.

Method for the treatment of schizofrenia in humans, comprising:

• administering a pharmaceutically effective amount of a compound of the formula:
• A.sub.1 -A.sub.2 -L-Phe-X-L-Thr-L-Ser-R.sub.1 -Y-L-Ser-R.sub.2 -L-Thr-L-Pro-L-Leu-L-Val-L-Thr-B
• wherein:
• (a) A.sub.1 and A.sub.2 each represent an L-amino-acid residue of the formula H.sub.2 N-ALK-CO-, wherein ALK is an alkylidene group with 1 to 6 carbon atoms;
• (b) X is an amino-acid residue selected from the group consisting of L-Met, L-Met(0), L-Met(0.sub.2) and L-Leu;
• (c) R.sub.1 and R.sub.2 each represent one of the amino-acid residues selected from the group consisting of L-Glu and L-Gln;
• (d) Y represents an amino-acid residue selected from the group consisting of L-Lys and D-Lys;
• and
• (e) B represents one of the peptides selected from the group consisting of L-Leu-OH, D-Leu-OH, 1-MeLeu-OH, L-Leu-L-Phe-OH, L-Leu-L-Phe-L-Lys-OH, L-Leu-L-Phe-D-Lys-OH and L-Leucinol.