"in the pancreas and brain" doesn't ever specify what species we're talking about (most evidence comes from mice), and leaves out the intestine, where FFAR1 has an important function. I'd add this information but don't know how to add citations. Itoh et al (2003) Nature 422(6928):173-6 shows the presence of FFAR1 in the intestine of mice, and DOI: 10.1152/ajpgi.00134.2014 talks about it in humans.