Pentagastrin is a synthetic polypeptide and cholecystokinin-2 (CCK
2) receptor agonist.
1 It binds selectively to CCK
2 receptors in guinea pig brain over CCK
1 receptors in rat pancreas (IC
50s = 11 and 1,100 nM, respectively). Pentagastrin increases calcium influx and polyphosphoinositide turnover in rat GH3 pituitary cells (EC
50s = 23 and 3.9 nM, respectively). It also increases histidine decarboxylase activity in mucous- and endocrine cell-enriched isolated rabbit fundic mucosal cells (EC
50 = 2.9 nM).
2 Pentagastrin induces contraction of isolated pig ileum smooth muscle cells
in vitro (EC
50 = 30 pM).
3 It increases gastric acid and pepsin secretion in conscious cats
in vivo (ED
50s = 1.29 and 57.3 nmol/kg
2 per hour, respectively).
4 Formulations containing pentagastrin have previously been used as a diagnostic aid to evaluate gastric acid secretory function.