L-Pyroglutamyl-L-histidyl-L-prolyl-beta-alaninamide and salts

A dipeptide of the formula

• Pro--NH--CH.sub.2 --CH.sub.2 --CO--NH.sub.2 (II)
• wherein the proline has the L-configuration.

A tripeptide of the formula

• His--Pro--NH--CH.sub.2 --CH.sub.2 --CO--NH.sub.2 (VI)
• wherein the amino acids containing an asymmetric center have the L-configuration.

A tetrapeptide of the formula

• R.sub.2 --pGlu--His(R.sub.3)--Pro--NH--CH.sub.2 --CH.sub.2 --CO--NH--R.sub.4 (VIII)
• wherein R.sub.2 is hydrogen or an amino protecting group, R.sub.3 is hydrogen or a group protecting the imidazole function and R.sub.4 is hydrogen or an amide protecting group, with the proviso that at least one of 4.sub.2, R.sub.2 and R.sub.4 represents other than hydrogen and the amino acids containing as asymmetric center have the L-configuration.

A tetrapeptide of the formula

• pGlu--His---Pro--NH--CH.sub.2 --CH.sub.2 --COX (IX)
• wherein X is hydroxy, a residue activating the carboxyl group or the residue --OR.sub.5 in which R.sub.5 is lower alkyl, aryl, aryl-(lower alkyl) or the residue of a polymeric carrier material and wherein the amino acids containing an asymmetric center have the L-configuration.

A tetrapeptide of the general formula

• R.sub.6 --His--Pro--NH--CH.sub.2 --CH.sub.2 --COY (X)
• wherein R.sub.6 is glutamine or glutamic acid residue which may be in protected form, Y is a residue activating the carboxyl group, the residue--NHR.sub.4, in which R.sub.4 is hydrogen or an amide protecting group, or the residue --OR.sub.5, in which R.sub.5 is lower alkyl, aryl, aryl-(lower alkyl) or the residue of a polymeric carrier material, and wherein the amino acids containing an asymmetric center have the L-configuration.