GCG and sclerosing cholangitis: Similarly, ICA ameliorates hepatic inflammation and fibrosis in a 3,5-diethoxycarbonyl-1,4-dihydrocollidine-induced primary sclerosing cholangitis model [27], and indole stimulates enteroendocrine L cells to produce glucagon-like peptide-1 (GLP-1), enhancing insulin secretion by pancreatic β cells in vitro [28].