Fig. 3 |. Effects of bile acids on metabolic processes throughout the body.

The primary sites of bile acid (BA) function are the liver and intestine, which are enriched in BAs and BA receptors. Through their ability to facilitate secretion of hormones such as glucagon-like peptide 1 (GLP1), fibroblast growth factor 19 (FGF19) and others, BAs can indirectly affect other tissues, including the brain. Furthermore, low levels of BAs are found in the systemic circulation, potentially enabling direct effects of BAs in tissues throughout the body. (R) indicates that supporting data were mostly from rodents; (H) indicates that supporting data were from humans, human cells or purified human proteins. Data were originally presented in the following effects in the central nervous system (CNS): peripheral glucose disposal⁵⁹ (R), energy expenditure⁵⁸ (R), and food intake¹⁹³ (R); effects in islets: endoplasmic reticulum (ER) stress^33,173 (R), and insulin secretion¹⁹⁴ (R); effects in the liver: gluconeogenic gene expression^48,56 (R), glycolytic gene expression^52,216 (R, H), glycogen synthesis⁵⁷ (R), hepatic triglyceride metabolism¹⁹⁵ (R), hepatic lipotoxicity⁴⁸ (R), and lipoprotein turnover^152,196 (R, H); effects in adipose tissue: immune cell infiltration⁹¹ (R), and thermogenesis⁵⁸; effects in the gut: lipid absorption^13,183,184 (R), vitamin absorption¹⁹⁷ (R, H), glucose absorption⁴⁹ (R), ceramide production^50,198 (R), N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD) activity^36,37 (purified human protein), GLP1 secretion^86–90,199 (R, H), peptide YY (PYY) secretion^90,199 (R, H), and FGF19 secretion¹⁹⁹ (R, H); and effects in skeletal muscle: lipotoxicity⁴⁸ (R).