The influence of peptides derived from corticotrophin (ACTH) on performance. Structure activity studies.

Publisher Summary This chapter describes the influence of peptides derived from corticotrophin (ACTH) on performance. In the study reported in the chapter, two approaches are followed. First, it sought the small peptide sequence of ACTH that possesses essentially the same behavioral effects as ACTH itself. Second, the chapter tries to increase the behavioral potency of the sequence ACTH 4-9 by introducing certain structural modifications. Attention is focused on the dissociation between behavioral activity and melanocyte stimulating hormone (MSH)-like potency. The influence of peptides derived from ACTH on acquisition and extinction of conditioned avoidance behavior in rats was studied. The tetrapeptide ACTH 4-7 is found to be the short peptide that still bears the essential elements required for the behavioral effects. The improved performance of hypophysectomized rats treated with ACTH or fragments of ACTH is neither due solely to improved motor and/or sensory capacities nor to an increase in the level of general activity.