Fibroblast Growth Factor 19: An Overview of its Diverse Physiological Functions

Fibroblast Growth Factor 19 (FGF19) is an intestinally derived member of the Fibroblast Growth Factor (FGF) family that governs embryonic development, tissue morphogenesis, tumor growth and invasion and nutrient metabolism. The most important function of FGF19 is to negatively regulate the first and rate-limiting enzyme Cholesterol 7 alpha-hydroxylase (CYP7A1) in bile acid synthesis acting by means of its highly specific receptor, Fibroblast Growth Factor 4 (FGFR4). It also stimulates gall bladder refilling thus serving as a feed forward signal for bile acid excretion and storage. Furthermore, FGF19 has been shown to participate in glucose and lipid metabolism via mechanisms that are comparable to insulin signaling. Currently, there is no detailed theory to explain the multifaceted nature of FGF19 but future studies might shed light on this important phenomenon. FGF19 is also highly expressed in Hepatocellular Carcinoma (HCC) and is responsible for growth and invasion of tumors through its interactions with FGFR4. Consequently, researchers are exploiting this ligand-receptor interaction to target cancer treatments. This review will highlight the current state of knowledge about the roles of FGF19 and its potential implications in clinical research and therapeutics.