Cynomolgus monkey gallbladder bile contains high concentrations of fibroblast growth factor 19

摘要

Fibroblast growth factor 19 (FGF19) is a unique member of the FGF family. It is one of the three secreted FGFs (FGF19, FGF21, and FGF23) that are devoid of mitogenic activity and can be released into the circulation to fulfill an endocrine mode of action.1"3 It is intriguing that Zweers et al.4 reported that human bile contains FGF 19. In fact, the levels of FGF 19 in human gallbladder bile are 100-fold higher than the circulating FGF19 (21.9 ± 13.3 ng/mL versus 0.22 ± 0.14 ng/mL).4 In addition, they showed that the FGF 19 gene is expressed in the adult human gallbladder, and high levels of FGF 19 can be secreted from gallbladder mucosal explants. This indicates that a major source of FGF19 in the bile is from mucosal cells of the gallbladder. On the other hand, the messenger RNA (mRNA) of FGF 15 (FGF 19 ortholog) was virtually undetectable in murine gallbladder. Thus far, the human species is the only species being reported to have a high concentration of FGF 19 in the gallbladder bile. To address the skeptical view of an endocrine factor appearing in an exocrine space, we examined gallbladder bile from cynomolgus monkeys (Macaca fascicularis) for the presence of FGF19. In addition, circulating concentrations of FGF 19 in monkeys and its responses to the presence and absence of bile acid was determined.