Oxytocin is a mammalian neurohypophysial hormone a ligand of oxytocin receptor.

Malonic acid (propanedioic acid) is the archetypal example of a competitive inhibitor: it acts against succinate dehydrogenase (complex II) in the respiratory electron transport chain. Malonic acid is found to be associated with malonyl-CoA decarboxylase deficiency which is an inborn error of metabolism.

Benzotript is an gastrin-receptor antagonist, with anti-gastrinic.proglumide and benzotript, a new tryptophan derivative, to inhibit acid output from isolated gastric fundic parietal cells from rabbit.