Pentagastrin Analogs Containing α-Aminooxy Acids, III. Biological Studies and Structure-Activity Relationships

Abstract
The stimulation of gastric acid flow by 36 new pentagastrin analogs administered i.v., intrajejunally and intrarectally was determined in rats. Some of the analogs are several times more active than the pentagastrin (Peptavlon, [Imperial Chemical Industries]) used as control. Unlike the control, some analogs are absorbed in active form from the jejunum. The N-terminal substitution with .alpha.-aminooxy acids seems to increase the gastric secretory response, probably by improving the enzymatic resistance of the molecule to various enzymes. None of the analogs tested significantly inhibit the gastric acid output in rats induced by pentagastrin. Structure-activity relationships are discussed.