[Hyp3]-tuftsin ([Hyp3]-TU) synthesis and biological activity

[Hyp³]-tuftsin (Thr-Lys-Hyp-Arg) has been synthesized by the liquid-phase method. In biological investigations performed on rats antinociceptive and diuretic effects have been determined. It has been suggested that the presence of hydroxyl substituent in pyrrolidine ring of proline slightly modifies antinociceptive TU effect and is responsible for the increased diuretic [Hyp³]-TU activity.