title: Relative potency of bombesin-like peptides.
abstract: The pharmacological activity of two natural bombesin-like peptides, alytesin and litorin, and 25 related synthetic peptides has been compared to that of bombesin. 2 The minimum length of the amino acid chain required for the first appearance of bombesin-like effects was represented by the C-terminal heptapeptide, and the minimum length for maximal effects by the C-terminal nonapeptide. The latter possessed approximately the same activity as bombesin and may be considered a good substitute. 3 Both the tryptophan and histidine residues seemed to be essential for bombesin-like activity. 4 The C-terminal octapeptide was less active than either bombesin or the C-terminal nonapeptide and its action was more rapid in onset and less sustained. 5 Litorin apparently has an intermediate position between bombesin octapeptide and bombesin nonapeptide in the speed and duration of its effects. The relationship between structure and activity is discussed.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001839:Bombesin / Q000494:pharmacology*; D002415:Cats; D004285:Dogs; D005260:Female; D005704:Gallbladder / Q000187:drug effects; D005750:Gastric Juice / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism; D005755:Gastrins / Q000378:metabolism; D066298:In Vitro Techniques; D007422:Intestines / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009842:Oligopeptides / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology*; D051381:Rats; D013329:Structure-Activity Relationship; D013997:Time Factors; D001743:Urinary Bladder / Q000187:drug effects; D014590:Uterine Contraction / Q000187:drug effects
chemical_list: D005755:Gastrins; D009842:Oligopeptides; D010455:Peptides; C000058:alytesin; D001839:Bombesin