Background:

Bombesin has common effects on the gastrointestinal tract and feeding behavior. Bombesin acts on two types of receptors including one with high affinity for neuromedin B and another with high affinity for bombesin and gastrin-releasing peptide (GRP). BIM 187is a new peptide of bombesin while BIM 189 is a potent bombesin antagonis.

In vitro: Bombesin stimulates mainly the bombesin high-affinity receptor, and BIM 187 ([D-Phe I ,Leu 8'9 ]litorin-NHe), a new bombesin agonist, stimulates the bombesin/GRP receptor type. [2].

In vivo: To study the mechanism by which bombesin induces satiety, we studied the effect of BIM187 on food intake in rats fed 6 h a day. BIM 187 at 4 μg/kg, reduced food intake at 30 min significantly, but did not change the total 6-h food intake. BIM 189 (10 mg/kg), had no effect on food intake, even at high doses (20 mg/kg). BIM 189 selectively reduced bombesin-induced satiety but had no effect on satiety induced by BIM 187 [2].

Clinical trial: Up to now, BIM 187 is still in the preclinical development stage.

Reference:
[1] Coy D, Wang LH, Jiang NY, Jensen R.  Short chain bombesin pseudopeptides with potent bombesin receptor antagonist activity in rat and guinea pig pancreatic acinar cells. Eur J Pharmacol. 1990 Nov 6;190(1-2):31-8.
[2] Laferrère B,?Leroy F,?Bonhomme G,?Le Gall A,?Basdevant A,?Guy-Grand B.  Effects of bombesin, of a new bombesin agonist (BIM187) and a new antagonist (BIM189) on food intake in rats, in relation to cholecystokinin. Eur J Pharmacol.?1992 Apr 29;215(1):23-8.