Neurotensin (8-13)

Neurotensin (8-13) is the smallest active fragment of neurotensin. Neurotensin(8-13) binds to the same sites as neurotensin. However, in the human brain, neurotensin(8-13) has a higher affinity for these sites than neurotensin does. The rapid degradation of neurotensin (NT) limits its clinical use in cancer imaging and therapy. Neurotensin(8–13) pseudopeptide, NT-VIII, was developed to sidestep this problem. Some changes were introduced to the sequence of neurotensin(8–13) to stabilize the molecule against enzymatic degradation: Arg8 is now N-methylated, and Lys and Tle have replaced Arg9 and Ile12, respectively. These have stabilized the molecule against enzymatic degradation without affecting its binding properties. Moreover, the increase in stability has enhanced tumor uptake, making this derivative a promising candidate for clinical use.