Afferent/efferent signaling does not regulate the effects of xenin-25 on GIP action. Following an overnight fast, mice (n = 4 per treatment group) were given an intraperitoneal injection of saline alone (“Saline”), glucose plus GIP (“GIP”), or glucose plus GIP plus xenin-25 (GIP+Xen or G+X). One hour later, brains were harvested for c-fos immunohistochemistry. Representative images of c-fos staining in the DMV and NTS, PVN, or ARC are shown. Brains from insulin injected hypoglycemic mice (“Insulin” or Ins) served as a positive control for induction of c-fos levels in the NTS, PVN, and ARC. A–D, the number of c-fos-positive cells was quantitated by morphometry. *, one-way analysis of variance indicates that variation among column means is significant (p < 0.01), and the Tukey-Kramer multiple comparisons test indicates that the differences in c-fos measured in the presence of insulin, compared with those obtained with saline, GIP plus glucose, or GIP plus glucose plus xenin in the PVN or insulin and GIP plus glucose plus xenin, compared with those obtained with saline or GIP plus glucose in the ARC, are statistically significant (p < 0.05).