Synthese des «Thyrotropin‐releasing» Hormons (TRH) (Schaf) und verwandter Peptide

The syntheses of seven tripeptide isomers containing L‐histidine, L‐proline and L‐glutamic acid residues, the same as found in the natural thyrotropin‐releasing hormone (TRH), are reported. In addition L‐pyroglutamyl‐L‐histidyl‐L‐proline and its amide as well as Nα‐acetyl‐L‐glutamyl‐L‐histidyl‐L‐proline are described. Whereas eight peptides are inactive and L‐pyroglutamyl‐L‐histidyl‐L‐proline shows a slight TRH activity, L‐pyroglutamyl‐L‐histidyl‐L‐proline‐amide has the full biological activity of the isolated thyrotropin‐releasing hormone and, at the present state of knowledge, seems to be identical with it.