Fig. 3.
Effects of a single icv injection of β-EP1–31 on NDP-MSH-induced suppression of feeding and body weight gain. A, After an overnight fast, cumulative refeeding was significantly suppressed by a single icv injection of NDP-MSH at 2, 4, and 8 h (n = 6–7/group). Concomitant β-EP1–31 injection reversed this suppression at 2 and 4 h. At 2 h the MSH and MSH+β-EP groups were significantly different from each another. At 8 h β-EP no longer antagonized MSH's effects. B, The MSH group gained significantly less weight at 4 and 8 h compared with the saline group. This effect was reversed by β-EP at 4 h but was no longer evident at 8 h. C, A 1-μg dose of β-EP1–31 alone in a fasting and refeeding model did not stimulate food intake, in fact food intake tended to be lower at the 2 h (P = 0.10) and 4 h (P = 0.09) time points. *, P < 0.05, **, P < 0.01, ***, P < 0.001 vs. saline; +, P < 0.05, ++, P < 0.01 vs. MSH.