Gastrin releasing peptide-29 evokes feeding responses in the rat

In mammals, gastrin releasing peptide (GRP) 10 and 27 reduce food intake. In the current work, we test the hypothesis that GRP-29, the large molecular form of GRP in the rat, also evokes feeding responses consistent with a possible role in satiety. Here, we measured three feeding responses, size of first meal, intermeal interval (IMI, time between first and second meal) and satiety ratio (SR, satiation period for every unit of food consumed in the first meal), in overnight food deprived rats following GRP-10, 27 or 29 (0, 0.3, 1.0, 2.1, 4.1, 10.3, 17.2 nmol/kg) intraperitoneally and presentation of a 10% sucrose test diet. GRP-29 and GRP-27 reduced the size of the first meal, prolonged IMI and increased SR, but GRP-10 failed to exhibit similar feeding responses. The order of potency was GRP-29 = GRP-27 > GRP-10. The current data support a role for GRP-29 in the short-term regulation of food intake.

Research highlights▶ GRP-29 may evokes feeding responses consistent with a possible role in satiety. ▶ We measured meal size, IMI and SR by GRP-29, 27 or 10. ▶ GRP-29 and 27 reduced the size of the first meal, and increased IMI and SR. ▶ The order of potency was GRP-29 = GRP-27 > GRP-10. ▶ There is a role for GRP-29 in the short-term regulation of food intake.