Neurotensin Hexapeptides

A pharmaceutical agent comprising, as an active ingredient, a hexapeptide of the formula (I):

• A-B-Pro-C-D-E (I)
• where A is an L- or D- form of arginine or lysine the N-terminal amino group of which is deaminated, B is an L- or D- form of arginine, lysine, or histidine, Pro is an L- or D- form of proline, C is an L- or D- form of tyrosine, tryptophan, or phenylalanine, D is an L- or D- form of valine, isoleucine, or leucine, and E is an L- or D- form of valine, isoleucine, or leucine, one of the hydrogen atoms of the amino group of which may be substituted with a C.sub.1 to C.sub.4 alkyl group, and the C-terminal carboxyl group of which is substituted with --CH.sub.2 OR , wherein R is a hydrogen atom or a C.sub.1 to C.sub.4 alkyl group, or a pharmaceutically acceptable salt of the hexapeptide;
• and
• a pharmaceutically acceptable carrier.

A pharmaceutical agent comprising, as an active ingredient, a hexapeptide of the formula (II):

• A-B-Pro-C-D-E (II)
• where A is an L- or D- form of arginine or lysine the N-terminal amino group of which is alkylated or acylated, B is an L- or D- form of arginine, lysine, or histidine, Pro is an L- or D- form of proline, C is an L- or D- form of tyrosine, tryptophan, or phenylalanine, D is an L- or D- form of valine, isoleucine, or leucine, and E is an L- or D- form of valine, isoleucine, or leucine, one of the hydrogen atoms of the amino group of which is substituted with a C.sub.1 to C.sub.4 alkyl group, and the C-terminal carboxyl group of which is substituted with --CH.sub.2 OR, wherein R is a hydrogen atom or a C.sub.1 to C.sub.4 alkyl group, or a pharmaceutically acceptable salt of the hexapeptide;
• and
• a pharmaceutically acceptable carrier.